Reference / Reference
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Short explanations of the course’s money, technology, and investing terms.
If a word stops you while reading, look it up here. Choose a topic below or use your browser’s find tool. This page is an optional reference, not another chapter you must finish.
Select a linked term to open its lesson. Each group starts with a few common terms; open “More terms” to see the rest. The definitions include limits that help prevent common mistakes.
Money · Banks · Financial base · Agreement · Origins · Keys · Payments · Mining · Rules
History · Ethereum · Stake · Applications · Pools · Research · Safety · Your plan
Money and purchasing power.
Money: Something people accept in payment, use to state prices, and keep for later spending. No kind of money does every job perfectly.
Ledger: A record of balances, claims, or payments. Ask who may change it, who checks changes, and how people settle disagreements.
Purchasing power: What an amount of money can buy. A larger account balance may still buy fewer goods if prices rise faster.
More terms about money and purchasing power
Barter: Trading a good or service directly for another. It helps explain a problem money can solve, but it is not a complete history of how every society developed money.
Double coincidence of wants: The need to find someone who wants what you offer and has what you want, at the right time. For example, a baker who wants shoes must find a shoemaker who wants bread.
Durable: Able to last through storage and use. Durable money does not quickly spoil or lose the qualities that make it useful.
Portable: Practical to carry or transfer. Weight matters for physical money; connections and access matter for digital payments.
Divisible: Able to be split into smaller usable units. This lets people make small payments as well as large ones.
Fungible: Interchangeable for the same purpose. Two units may have the same stated value yet be treated differently if restrictions or their histories matter.
Scarce: Limited compared with how much people want. A low supply alone does not give people a reason to want something.
Rai stones: Large stone money associated with Yap. People could recognize a new owner without physically moving the stone.
Debasement: Reducing the precious metal in money, such as replacing some silver with copper. For a coin, the stated value may stay the same. People also use the word more loosely for other declines in money’s quality.
Stock: The amount already in existence at a stated time. Check whether an estimate includes lost units or units nobody can access.
Flow: The amount added during a stated period. To compare monthly and yearly production, first put them in the same time units.
Stock-to-flow: The existing amount divided by the amount newly produced in a year. It describes supply; it does not calculate or guarantee a market price.
Hard money: Money whose supply is relatively hard to increase. Its price or buying power can still fall.
Easy or soft money: Money whose supply can increase more easily. That label alone does not explain a particular inflation rate or how a person will behave.
Banks, prices and time.
Fiat money: A government currency that does not promise a fixed amount of gold or another commodity in return. Laws, institutions, economic activity, and confidence help people accept it.
Inflation: A broad rise in prices over time. Each unit of money then buys less of the measured goods and services. Several forces can contribute.
Custodian: A person or organization trusted to hold assets or the keys to them. You depend on its ability and willingness to keep its promises.
More terms about banks, prices and time
Bank deposit: Money the bank records as owing to a depositor. It is a claim on the bank, which differs from holding cash directly.
Fractional-reserve banking: Banking in which every dollar of deposits is not matched by a dollar of immediately available reserves. Modern banks can create deposits when they lend. They still face limits from funding, ready money, and capital that can absorb losses.
Bank run: Many customers asking for their money at once. A bank can struggle to turn long-term assets into enough cash right away.
Bretton Woods: The system agreed in 1944 that linked participating currencies to the dollar. Foreign official dollar holdings could be exchanged for gold under its rules. The U.S. suspended that gold link in 1971.
Reserve currency: A currency held by central banks or similar authorities for reserves, international payments, and managing exchange rates. That role does not promise permanent dominance.
Cantillon effect: The idea that new spending power reaches people at different times. Some prices and people can be affected before others. This does not explain every unequal outcome on its own.
Time preference: How much a person values using resources now compared with later. Needs, resources, and uncertainty affect the choice. Patience is not a test of someone’s moral worth.
Nominal and real returns: A nominal return measures growth in money units. A real return adjusts for changed buying power. For the exact result, divide the money growth factor by the price growth factor, then subtract one.
Your financial base.
Take-home income — Pay left after payroll deductions. Someone who works for themselves must plan separately for taxes and business costs. See the monthly gap.
Planning gap — What is left from monthly take-home income after planned living costs, required payments, and money for irregular bills. You can then decide which further goals should receive the remainder.
Sinking fund — Money saved a little at a time for a bill you know is coming. It differs from money held for surprises.
Emergency fund — Money you can reach for an unexpected essential cost or a break in income. The amount needed depends on the household.
Net income from a side activity — Money earned minus the costs of earning it. Also consider taxes and the time the work takes. Compare income routes.
Transferable skill — An ability you can use in more than one kind of work. Give an example of using it, rather than just claiming you have it.
Career hypothesis — A possible work direction to investigate. Compare it with your skills, limits, and real job openings, then test the idea. It is not a prediction of your future. Build a career shortlist.
Compounding — Each percentage change acts on the balance left by the last one. A gain or loss therefore changes the amount used in the next calculation. Deposits, withdrawals, and costs can also change the balance. Explore addition and multiplication.
Agreement without one bookkeeper.
Consensus: The rules and process a network uses to agree on a record. Checking whether entries are allowed and choosing between valid histories are different parts of that job.
Centralization: Control or dependence gathered in a small number of hands. Ask what is controlled, who controls it, and whether other people can act independently.
Decentralization: Control or checking spread among independent participants. Different parts can be more or less decentralized. A large server count alone does not prove independence.
More terms about agreement without one bookkeeper
Double-spend problem: The problem of stopping the same digital funds from paying two recipients. Copying a payment message must not create more spendable money.
Digital balance integrity: Keeping the creation and spending of digital money within the rules, including stopping double spending. Some call this “value containment.” It does not guarantee the money’s market price.
Byzantine Generals Problem: A model of how people or computers reach agreement when some fail or send conflicting messages. Blockchains tackle particular versions of this problem under stated assumptions.
Sybil attack: One person or group making many identities to gain influence. Work- or stake-based systems aim to prevent extra names alone from creating extra power.
Peer-to-peer: Participants connecting with one another instead of depending entirely on a central service. A direct connection does not, by itself, make the other participant trustworthy.
Distributed record: A record copied in several places. One organization can still control all those copies.
Validity rules: Conditions a transaction or block must meet. More work or stake cannot make an entry that breaks those conditions valid.
Fork choice: A rule for choosing among competing histories that pass the needed checks. It works alongside validity checks, not as a replacement for them.
Most-work rule: Bitcoin’s rule favoring the valid chain with the most total proof of work. Counting blocks alone is not enough, because their required work can differ.
Blockchain: A record divided into blocks linked by digital fingerprints called hashes. Those links are only part of security; checking rules, reaching agreement, and operating the system also matter.
The constitution analogy: A teaching comparison with a shared rulebook. Validity says what is allowed, while consensus helps participants agree on the history. Software is not a literal constitution, court, or vote by every person.
The ideas before the network.
Whitepaper: A document that proposes or explains a design. It can show the author’s plan, but it is not an audit or proof that the design works.
Satoshi Nakamoto: The name used by Bitcoin’s author or authors. The public record shows their work; it has not established a confirmed real-world identity.
Genesis block: The first block in a blockchain. Bitcoin’s dates to January 2009.
More terms about the ideas before the network
DigiCash: A company linked to David Chaum’s electronic-cash designs. Its use of cryptography helped protect privacy, but the system still depended on an issuer.
e-gold: An internet payment system with balances linked to gold held centrally. Users still depended on the custodian and the legal system around it.
Hashcash: Adam Back’s design for making messages cost computer work to produce. It was an important idea, not the complete Bitcoin money system.
b-money: Wei Dai’s proposal for distributed digital money. It contributed ideas, but it did not become the same running system as Bitcoin.
Bit Gold: Nick Szabo’s proposal using costly digital work and ownership records. It came before Bitcoin; it was not simply another name for Bitcoin.
Hal Finney: A cryptographer and early Bitcoin user. His written account describes receiving an early transaction from Satoshi and provides evidence about that history.
Keys and custody.
Private key: A secret number used to sign and authorize actions. Someone who gets enough of the required keys can act as the holder.
Wallet: Software or hardware that helps manage keys, addresses, and transactions. The network keeps the ownership record; the device does not contain the coins themselves.
Seed or recovery phrase: A readable backup that many wallets use to rebuild keys. The required format, extra passphrase, and other recovery information depend on the wallet.
More terms about keys and custody
Public key: Information linked by mathematics to a private key. It helps check signatures without revealing that secret key.
Address: An identifier or payment destination. Its format and meaning depend on the network, and the address alone does not identify a person.
Digital signature: A mathematical proof that the required key authorized specific data. It does not prove that the deal is honest or the program is safe.
Custodial wallet: A service that controls the keys for you. You rely on its account access, recovery, and withdrawal procedures.
Self-custody: An arrangement where you control the keys or other authority needed to sign. You also take responsibility for protection and recovery.
Hot wallet: A wallet with private keys in software connected to the internet. Those keys face that environment’s risks. A hardware signer that keeps keys isolated does not become hot merely because it connects to a computer.
Cold storage: Keeping signing secrets offline. They still need to be created safely, backed up, and used only after checking the transaction.
a later lesson: A device built to keep keys in a separate signing environment. Its trusted screen helps you check what you are approving.
Multisig: Spending rules requiring several keys, such as two out of three. Recovery may need the wallet’s setup information as well as enough surviving keys.
Counterparty risk: The risk that someone you depend on fails, refuses to act, or cannot meet their promise.
a later lesson: An extra secret used by some backup systems to create a different wallet. The same recovery words with a different passphrase can restore different accounts.
A payment becomes a record.
UTXO: An unspent transaction output: a piece of bitcoin with rules for spending it. A new payment spends earlier outputs and creates new ones.
Node: A computer taking part in a network. A full validating node checks the rules. A pruned node can do those checks without keeping every old block file.
Confirmation: A transaction first has one confirmation when it is included in a block. Later blocks built on that block add confirmations. More confirmations reduce some reversal risks, without removing every risk.
More terms about a payment becomes a record
Change: Value sent back to the sender in a new Bitcoin output. It is needed when the spent inputs are worth more than the payment plus its fee.
Mempool: A node’s collection of unconfirmed transactions it currently accepts. Different nodes can have different collections; there is no single identical waiting room everywhere.
Transaction fee: A payment for including or executing a request under network rules. The needed resources and demand affect the fee, so it is not based only on how much money you send.
Block: A group of transactions and related information proposed or accepted together under a network’s rules.
Hash: A fixed-size digital fingerprint calculated from data. A secure hash helps reveal changes to that data. It does not hide the data by encrypting it.
Avalanche effect: The way a tiny change in input makes a hash look very different. It helps reveal an edit; it does not make editing physically impossible.
Collision: Two different inputs producing the same hash. Such pairs must exist because a hash has a fixed size. A secure design makes useful matching pairs impractical to find.
Block header: The small set of block information used for links and checks. Bitcoin’s header commits to the previous block and to the block’s transaction data.
Merkle tree and root: A tree-shaped set of hashes summarized by a single root hash. It can provide a short proof that a particular item belongs to the data recorded under that root.
Immutable or immutability: Hard to change under stated conditions. It does not put blockchain history beyond bugs, reorganizations, or rule changes people adopt.
Reorganization: A switch from part of the accepted chain to another eligible branch. Recent payments may become pending again or conflict with payments on the new branch.
Work, energy and issuance.
Proof of work: A system in which producing acceptable evidence requires costly computer work, while checking it is much easier. Bitcoin uses that work to help order valid history.
Mining: Building a candidate block and trying hashes until one is at or below the required target. Finding that hash does not excuse a block that breaks other rules.
Halving: A scheduled cut by half in Bitcoin’s block subsidy, every 210,000 blocks. The date is approximate, and the cut does not promise a price rise.
More terms about work, energy and issuance
Nonce: A number miners change while searching for an acceptable block hash. They can also change other candidate data to create more attempts.
Target and difficulty: The target is the highest acceptable hash value for proof of work. A smaller target makes success harder on average. Difficulty describes how hard that target is to meet.
Hashrate: The number of hash attempts per unit of time. Network hashrate is estimated from blocks and difficulty, not counted by one central meter.
Difficulty adjustment: Bitcoin’s change to its work target, ordinarily every 2,016 blocks. It aims to keep the average pace near the intended block interval. Individual gaps still vary.
Coinbase transaction: The first transaction in a Bitcoin block. It can claim the permitted subsidy and transaction fees. It is unrelated to the exchange named Coinbase.
Block subsidy: The new coins a valid block may create under the supply rules. Transaction fees are a separate possible source of miner income.
ASIC: An application-specific integrated circuit: a chip made for a particular task. Bitcoin miners commonly use chips designed for its hashing work.
51% attack: An attack using a majority of hashpower. It can make some blocking and history-reversal attacks practical. It cannot forge someone else’s signature or make nodes accept unlimited new coins.
Stranded energy: Energy with few other useful buyers in that place or at that time. Whether mining uses it, and what environmental cost results, depend on the situation.
Antifragile: A word for something that improves through certain stresses. Applying it to Bitcoin is an idea to test, not a promise that every attack strengthens the system.
Issuance: The creation of new money units under a system’s rules. More units being issued is different from their market price changing.
21 million: The familiar description of Bitcoin’s upper scheduled supply under current rules. It does not mean every issued bitcoin remains accessible.
Satoshi or sat: One hundred-millionth of a bitcoin. Fractions can be bought or transferred, but provider minimums and network fees may make tiny amounts impractical.
Rules and changes.
Consensus rules: The conditions participants apply when checking transactions and blocks. Today’s accepted rules are different from a proposal about what the rules should become.
Governance: How people propose, examine, and adopt changes. Software developers, businesses, users, and the protocol’s design all influence the process.
Fork: A split in chain history or a difference in protocol rules. A temporary branch does not always become a lasting separate asset.
More terms about rules and changes
BIP: A Bitcoin Improvement Proposal: a written proposal or standard. Publishing it does not automatically approve or activate it.
Soft fork: A rule change that allows a narrower set of blocks. Older software can accept blocks following the new rule, even though it does not enforce the added restriction itself.
Hard fork: A change that can allow blocks the old rules reject. A lasting split depends on who adopts it and whether people keep supporting both branches.
Open source: Software licensed so people can use, inspect, change, and share the code, including for business use. Being able to read it is not enough. Open source also does not mean an audit has happened.
Ossification: A preference or trend toward making fewer protocol changes. This can reduce the risk of changes while making adaptation harder. It is not an absolute state the software reaches.
a later lesson: A short name for tensions between spreading control, maintaining security, and handling more activity. It helps frame design choices; it is not a proven equation that settles every design.
a later lesson: A base blockchain with its own system for checking transactions and agreeing on history.
a later lesson: A system that does some work outside a base chain but depends on it for stated settlement or security functions. Different designs provide different protections.
a later lesson: A network of Bitcoin payment channels. It can route payments without putting every update on the base chain. It needs available funds along the route and reliable operation.
a later lesson: An arrangement where participants update balances between themselves and can later settle under base-chain rules. Opening, closing, and settling disputes each have conditions.
a later lesson: Money sent to another place, often another country. Count conversion, access, and cash-out costs as well as the network fee.
a later lesson: A Bitcoin upgrade that changed spending rules. It offers some efficiency, flexibility, and privacy benefits, but does not make every payment private.
a later lesson: A system for identifying individual satoshis. Under its conventions, inscriptions link data with them. This does not automatically give copyright or make every app support the data.
Names from the history.
a later lesson: A large early bitcoin exchange that failed in 2014. The case shows risks in trusting a custodian, running a service, and recovering losses.
a later lesson: A dispute about how Bitcoin should handle more activity and who should adopt changes. It shows that a technical choice also involves decisions by people.
a later lesson: An Ethereum investment project whose contract was exploited in 2016. People disagreed about recovery, leading to a fork and two continuing histories.
More terms about names from the history
a later lesson: The documented 2010 pizza purchase for 10,000 BTC. Later bitcoin prices do not tell us what the people involved knew at the time.
a later lesson: A service that gives out small amounts of an asset. Early ones helped people try a network. A present-day offer using the name can still be a scam.
a later lesson: A user-activated soft fork. Participating nodes enforce the activation rules in their software. The term does not mean each node has one equal vote over governance.
a later lesson: Segregated Witness: a Bitcoin upgrade that changed how signature-related data is represented and introduced rules based on block weight.
a later lesson: An initial coin offering raises money by selling or distributing tokens. The sale alone does not establish buyer rights, safety, or lawful status.
a later lesson: A loose name for a long downturn in crypto prices or activity. There is no single rule for its exact beginning or end.
a later lesson: Assets in the system whose stablecoin mechanism collapsed in 2022. The case shows that a design meant to stabilize a price can fail under pressure.
a later lesson: A crypto exchange that collapsed in 2022 amid misuse of customer funds. A balance at an exchange is a claim on the organization, not direct control of its assets.
a later lesson: An exchange-traded product with exposure through holdings of the underlying asset. Buying shares also involves the product’s fees, custody, and market risks.
a later lesson: An exchange-traded product that uses futures contracts. Contract prices, replacing expiring contracts, and fees can make its result differ from holding the asset itself.
a later lesson: The network that continued Ethereum’s history without the 2016 DAO recovery change. It reflects a real disagreement about whether to intervene.
a later lesson: An early Ethereum app with collectible tokens. Its activity showed interest in shared-chain apps and made the network’s limited capacity visible.
a later lesson: Ethereum’s 2024 upgrade that added temporary blob data space for rollups. Cheaper data does not remove every fee or risk of using a rollup.
a later lesson: Ethereum’s September 2022 move from proof of work to proof of stake. Its method of reaching agreement changed while the existing balances and application history continued.
Programs on a shared record.
a later lesson: A program stored on a blockchain that runs under the network’s rules when called. It can carry out a useful agreement or faithfully repeat a coding mistake.
a later lesson: Ethereum’s measure of computer work. Used gas multiplied by its price gives the execution fee. An included request that fails can still use paid gas.
a later lesson: Ether, the native Ethereum asset used for protocol fees and staking. An app may pay fees for a user, but the system’s work is still paid for.
More terms about programs on a shared record
a later lesson: The author of the original Ethereum whitepaper and one of its co-founders. Many other people also contribute to the network’s development.
a later lesson: A comparison for a network that runs shared programs and agrees on their results. Repeating the work has a cost, so it is not a cheap replacement for every ordinary computer.
a later lesson: Able, in principle, to express general computer tasks. Real Ethereum transactions still have resource limits such as gas; they cannot run forever.
a later lesson: A programming language commonly used for Ethereum contracts. Choosing the language does not guarantee that a particular program is safe.
a later lesson: A way of keeping balances and other information in accounts, then updating those records. Bitcoin organizes spendable value differently, using unspent transaction outputs.
a later lesson: An account controlled through a private key. Modern Ethereum can add delegated code behavior to it, so it is outdated to say such an account can never have code.
a later lesson: An account with program code and stored records. Its code runs when called during execution; it does not wake itself up.
a later lesson: The Ethereum Virtual Machine. Its rules define how compatible program instructions run and change stored records.
a later lesson: The network’s currently accepted records, including balances, account information, and stored contract values.
a later lesson: An asset defined by the network’s own rules, rather than issued by an app running on it. Being native does not guarantee market value.
a later lesson: Ethereum’s fee design with a burned base fee and a priority fee that encourages inclusion. Burning some ETH does not guarantee the total supply falls.
a later lesson: A common interface for interchangeable tokens on Ethereum-compatible systems. Shared functions make tokens easier for apps to use. They do not certify the token’s value or economics.
a later lesson: A common interface for distinct tokens, each with its own token ID. It sets token behavior, not automatic legal rights.
a later lesson: A connection for assets or information across networks. Check how it holds assets and verifies messages; the token’s name does not explain these extra assumptions.
a later lesson: A system that runs batches outside a base chain and connects the results back to it. It publishes data to the base chain so others can rebuild its state, along with a claim or proof about the result. Available data, checking rules, and administrator controls all affect its safety.
a later lesson: A rollup that gives people a defined period and process to challenge invalid results. Its safety depends on that process working.
a later lesson: A rollup using a cryptographic proof to show that its changes followed the rules. The “ZK” name does not, by itself, mean users’ transactions are private.
a later lesson: Calling into a contract again before an earlier call finishes. It becomes dangerous if the new call can use records that are inconsistent or unprotected. A callback is not always a bug.
a later lesson: A way of giving a contract information it cannot get directly from its own chain, such as an outside price. Recording the information on-chain does not prove it is true.
Stake and finality.
a later lesson: A way to support agreement using committed assets. The amount of stake affects influence, and rules set financial consequences for specified failures or attacks.
a later lesson: A participant with duties such as proposing blocks and signing views of the chain. Ethereum weights its influence using effective stake, rather than counting every identity equally.
a later lesson: A stage of agreement where reversing history would require an exceptional failure or broken assumptions. Ethereum’s finality procedure differs from Bitcoin’s growing number of confirmations.
More terms about stake and finality
a later lesson: Committing assets to support specified network duties. Running a validator, joining a pool, and holding a liquid-staking token involve different risks.
a later lesson: A validator’s signed statement about its view of the chain. The rules use these weighted statements to help choose history and establish finality.
a later lesson: A penalty for specified violations that can be proved, such as conflicting signatures. Ordinary missed-duty penalties are different.
a later lesson: A penalty for failing to take part. Ethereum also has rules that reduce inactive stake’s relative weight when finality is delayed. Going offline does not automatically mean slashing.
a later lesson: A service that issues a token representing a claim associated with staked assets. That token adds questions about code, operators, market price, and redemption.
The Web and on-chain applications.
a later lesson: Loose names for web publishing, large interactive platforms, and apps using wallets or shared records. The patterns overlap. Each new name does not replace everything that came before.
a later lesson: Decentralized finance: financial apps using smart contracts, often for trading or loans. Their websites, shared services, and governance can still concentrate control.
a later lesson: A token designed to stay near a target value, often one dollar. Designs use different reserves, collateral, and redemption rules. The target price can fail.
More terms about the web and on-chain applications
a later lesson: The internet connects networks. The web lets us use linked pages and information over those connections. It is one use of the internet, not the whole thing.
a later lesson: Using a key and signature to connect to an app or approve actions. Using the same wallet does not make every app recognize the same assets or rights.
a later lesson: A decentralized autonomous organization: people coordinating through some mix of contracts and group decisions. Check who holds votes and administrator keys, and what legal arrangements apply.
a later lesson: DAI is a token aimed at a dollar value. MakerDAO is the protocol historically linked to creating it against collateral. Their rules and governance have changed over time, so the names alone do not explain current risk.
a later lesson: Having pledged assets worth more than the loan. That extra value gives a margin, but a price fall, outdated price data, or failed liquidation can still cause losses.
a later lesson: A forced sale or closure under a position’s rules when it no longer meets requirements. Fees and fast price changes can make the result worse.
a later lesson: Supplying or moving assets to earn fees, interest, or reward tokens. A high displayed rate may include temporary rewards and leave out important risks.
a later lesson: The course’s question for an advertised return: who pays it, why do they pay, and what could stop the payments?
a later lesson: A non-fungible token: a distinct identifier recorded on a blockchain. The associated picture, permissions, and copyright depend on separate arrangements.
a later lesson: A comparison with gold that emphasizes scarcity and a possible role for saving value. It is an investment idea to examine, not a promise of stable prices.
a later lesson: A strong preference for one network or asset, sometimes rejecting all others. The preference is a viewpoint, not technical evidence.
Markets made from pools.
a later lesson: An automated market maker uses a contract to trade against pooled assets. It does not need to find a separate seller to answer each trade because the inventory is already there.
a later lesson: Someone who puts assets into a pool and receives a position that may earn fees. Trades change the mix of assets behind that position.
a later lesson: The gap when a pool position does worse than keeping its original tokens. The pool’s changing mix of assets creates the comparison as relative prices move. The gap is not guaranteed to disappear.
More terms about markets made from pools
a later lesson: A family of exchange protocols and related interfaces. Different versions and individual pools have different features and risks.
a later lesson: The assets the pool holds under its accounting rules. This is different from the total market value of all units of a token.
a later lesson: A mathematical relationship that trades must satisfy. A real pool may adjust it for fees.
a later lesson: A design commonly taught with x × y = k: A reserves times B reserves equal a fixed product. In the simple fee-free model, taking more of one token makes the next bit cost more of the other.
a later lesson: Trading across markets with different prices to seek a profit. It can bring pool quotes closer to outside prices while changing what providers hold.
a later lesson: The price movement caused by your own trade. When less liquidity is available, the same trade usually moves the price more.
a later lesson: The difference between the result you expected and the result you get. A slippage limit can reject an unacceptable result, but it does not prove that the original quote was fair.
a later lesson: A pool design for assets expected to stay near a common value. If that relationship breaks, providers can end up holding more of the weakened asset.
a later lesson: A pool with chosen shares of asset value, which need not be equal. Its pricing rule uses those weights and balances to determine trades and inventory.
a later lesson: Assets supplied for trades within a chosen price range. Outside that range, the position can become entirely one asset and earn no swap fees while inactive.
a later lesson: Optional code that runs around specified pool actions in systems such as Uniswap v4. Extra flexibility means extra rules and controls to understand.
a later lesson: Maximal extractable value: gains sought by deciding which transactions run, which are left out, or what order they run in. Some forms add costs for other traders.
Looking behind a token.
a later lesson: A quoted token price multiplied by estimated circulating supply. It is not money deposited in the project, guaranteed sale proceeds, or ownership of a company.
a later lesson: The ability to trade a given amount without moving the price too far, using a market you can actually access. A large headline value does not prove that such a market exists.
a later lesson: The rules for a token’s supply, distribution, rewards, and any rights. A useful product does not automatically make its token valuable.
More terms about looking behind a token
a later lesson: A broad informal name for crypto assets other than bitcoin. It includes very different purposes and risks.
a later lesson: A chain has its own network agreement system. A contract is an app deployed on a network. Sharing a network does not remove the contract’s own risks.
a later lesson: A token whose demand often comes from a joke, identity, or community. The label does not prove lasting demand or enough buyers when holders want to sell.
a later lesson: An asset or network designed to hide particular transaction information. What it hides, how to use it safely, and its legal treatment vary.
a later lesson: A story about why an asset should matter. Test the story against actual use, rights, costs, and risks rather than treating it as evidence by itself.
a later lesson: A unit price multiplied by a broader stated supply amount. Check which supply figure is used. The current price may change as more units become available.
a later lesson: The release of restricted tokens, or the schedule for releasing them. Being able to sell does not mean every holder will sell.
a later lesson: The buyers or pool assets that can absorb a sale. The phrase can also mean people persuaded to buy the holdings insiders want to sell.
a later lesson: How often an outcome occurs in a clearly defined group. Looking only at visible winners leaves out the rest of that group.
a later lesson: Trading arranged to look more independent than it is, such as one person moving assets between their own accounts. The displayed volume can give a misleading picture.
a later lesson: A possible outcome in which a few participants take a large share of a market. It is not a law that identifies which token will win.
a later lesson: A short, checkable explanation of a project’s purpose, control, token role, supply, liquidity, and possible failures. The reasoning and evidence matter more than the page length.
a later lesson: The strongest reason a project or investment idea could fail. Explain how failure could happen and what evidence would support the concern.
a later lesson: The identifier of a deployed contract on a particular network. A familiar token name or symbol is not enough to identify the right contract.
a later lesson: A loose name for insiders abandoning a project or taking value through their controls. Examples include draining pool assets, creating more tokens, or abusing administrator powers.
Protecting access and decisions.
a later lesson: A trick to obtain secrets, account access, or permission. It often imitates a person, website, or app you trust.
a later lesson: Permission for a named spender to move tokens within stated limits. Connecting to a website and giving that permission are separate actions.
a later lesson: A supported check or careful rehearsal showing that a backup restores the intended wallet. Do not begin by erasing a wallet that holds funds.
More terms about protecting access and decisions
a later lesson: Two-factor or multifactor authentication: requiring different kinds of evidence to sign in. The chosen factors and recovery routes affect the protection.
a later lesson: A public-key sign-in credential tied to a service. When properly implemented, it can resist fake websites better than a code you type into a page.
a later lesson: An attacker taking control of a phone number through the carrier or a compromised account. The attacker may then receive calls or recovery texts.
a later lesson: A small transfer used to check a route. Its success does not verify the address, asset, network, memo, or permission used in a later transfer.
a later lesson: Extra information a service may need to credit the correct account. Even the right address may not be enough without the required memo or tag.
a later lesson: A device or setup changed to expose secrets or trick you into approving actions. Recovery words supplied by a seller are a serious warning sign.
a later lesson: Keeping long-term holdings apart from frequent app use. Accounts made from one leaked seed do not protect one another from that same seed leak.
a later lesson: A signed message that can grant a token allowance in a supported design. It may give spending power even when signing costs no gas right away.
a later lesson: Disconnecting ends the website connection. Revoking changes an on-chain allowance. Neither makes leaked recovery words secret again.
a later lesson: A fraud that builds personal trust before directing someone toward a fake investment. It is sometimes called “pig butchering.” The scammer is responsible for the abuse.
a later lesson: Putting a look-alike address into someone’s transaction history, hoping they copy it for a later payment. Verify the destination through a separate trusted route.
a later lesson: Malicious software that changes copied text, such as a payment address. Check the complete destination on a trusted screen.
a later lesson: Promoting and buying an asset to draw in other buyers, then selling into that demand. The apparent excitement may be coordinated.
a later lesson: Look for demands for secrets, time pressure, guaranteed results, unexpected contact, and requests for more money. These clues help you investigate; you still need to check the actual action and recipient.
a later lesson: A second fraud that promises to get lost money back, often for an upfront payment or more access. A stranger’s guarantee is not evidence that recovery is possible.
Risk, cycles and a private plan.
a later lesson: Money you can reach for unexpected essential needs. The right amount depends on bills, income stability, and other support available.
a later lesson: Using borrowing or derivatives to increase exposure beyond the money put in. Losses can quickly use up that money and force a position to close before the asset reaches zero.
a later lesson: A fall from an earlier peak. Falling from 100 to 50 is a 50 percent loss. Returning from 50 to 100 requires a 100 percent gain, before fees and taxes.
More terms about risk, cycles and a private plan
a later lesson: A signal to identify what remains unresolved, such as bills, debt, loss capacity, knowledge, or custody. Waiting while you work through it is a valid choice.
a later lesson: An action that can have tax consequences under the rules that apply to you. In the U.S., selling, swapping, or spending can realize gains or losses. Rules differ elsewhere.
a later lesson: The time an asset has been held under the relevant tax or investment definition. Tax treatment depends on the place and facts involved.
a later lesson: The amount assigned to an asset for tax accounting. It is compared with sale proceeds to work out a gain or loss under the applicable rules.
a later lesson: Dollar-cost averaging: putting a fixed amount into an investment at regular times. It sets a purchase schedule; it does not remove the possibility of loss.
a later lesson: Buying gradually, or a name people give to a quieter market phase. A chart alone cannot reveal what every participant intends.
a later lesson: Intense excitement about speculation. It describes behavior; it does not reliably identify the exact market top.
a later lesson: A lasting market decline. People often use a fall of 20 percent from a peak as a guide, but definitions and time periods differ.
a later lesson: Asking how a loss, or a long delay in accessing money, would affect essential needs. Being able to imagine handling a loss does not make the asset safe.
a later lesson: Changes in how easy borrowing is and what it costs. These can increase spending and asset demand, then deepen a later pullback. They do not fix a crypto calendar.
a later lesson: Fear of missing out: feeling rushed by gains you imagine other people making. It tells you about a feeling, not the next market price.
a later lesson: Fear, uncertainty, and doubt. The label is often used to dismiss criticism. Examine the evidence behind a concern instead.
a later lesson: An intense good feeling that can make uncertainty seem less serious. Feeling sure is not proof that an investment is sound.
a later lesson: Giving up and selling, often after a painful decline. It does not prove the market has reached its final low.
a later lesson: Crypto slang for holding. It came from a December 2013 Bitcoin forum post titled “I AM HODLING.” The misspelling became a slogan, not a rule for whether holding suits your situation.
a later lesson: Keeping a position longer than very short-term trading. Definitions vary. A longer holding period does not erase risk or tax consequences.
a later lesson: Careful, ongoing work to check evidence and follow a sensible process. It can improve a decision without guaranteeing the result.
The idea to keep
You do not need to memorize this page. If a short definition is not enough, follow its lesson link and work through the example. Then return to what you were reading.