Bitcoin Glossary: 130+ Terms in Plain English

A

Address Poisoning: A scam where an attacker sends a tiny "dust" transaction from a newly-generated address whose first six and last six characters match the victim's real counterparty. The hope is that the victim will copy the attacker's address from their own transaction history. Defense: verify the full address on the hardware wallet's screen.
Air-Gapped: A hardware wallet that never connects to a phone, computer, or the internet. Transaction signing happens via SD card or QR code instead of USB or Bluetooth. Considered the most secure hardware-wallet architecture because the device's keys can never be reached by network-borne attacks. Foundation Passport Core is the standard air-gapped pick; SeedSigner is the DIY alternative.
Airdrop: A free distribution of a new token to selected wallets, often used to bootstrap a project's launch or reward early users. The project decides who qualifies and how much each address receives, so an airdrop still concentrates initial supply even when no money changes hands.
Altcoin: Any cryptocurrency other than Bitcoin. CoinGecko had listed nearly 20.2 million of them by the end of 2025, and reports that more than half have stopped trading.
Anchor Load: A customer that buys whatever excess electricity a power plant generates beyond local demand. Bitcoin mining can serve this role for remote micro-grids because it can absorb any amount of capacity, pays in globally liquid money, and steps aside when the local community needs the power.
Austrian Economics: A school of economic thought emphasizing free markets, sound money, and minimal government intervention. Austrian economists view inflation as an expansion of the money supply that transfers wealth from savers to those closest to the money printer.

B

Bearer Asset: An asset where possession equals ownership. Whoever holds it, owns it; no registry or third party needed. Physical cash and bitcoin are bearer assets; stocks and bank balances are not.
Bitcoin: A decentralized digital currency with a fixed supply of 21 million coins. It combines the scarcity of gold with the convenience of digital money. No central authority controls it.
Bitcoin Address: A string of characters you share with others to receive bitcoin. Derived from your public key. Think of it as your email address, safe to share publicly.
Bitcoin ATM: A physical machine that lets you buy bitcoin with cash. Convenient but expensive: average US buy fees 10–15%, with round-trip costs that can hit 17%.
Block: A bundle of transactions that has been verified and permanently recorded on the blockchain. A new block is added roughly every 10 minutes.
Block Confirmation: When a transaction is included in a mined block on the blockchain. Each subsequent block adds another confirmation. More confirmations = more finality. One confirmation takes approximately 10 minutes.
Block Explorer: A website that lets you search and view transactions, blocks, and addresses on the Bitcoin blockchain. Mempool.space is the most popular. Everything on the blockchain is public.
Block Reward: The new bitcoin a miner earns for successfully adding a block to the blockchain. Currently 3.125 BTC. Halves approximately every 4 years.
Block Size War: A multi-year conflict (2015–2017) within the Bitcoin community over whether to increase the block size limit. Thousands of individual node operators rejected the corporate-backed proposal, proving that Bitcoin's rules are enforced by users, not miners or companies.
Blockchain: A chain of blocks: the public, permanent ledger that records every Bitcoin transaction ever made. Every node on the network has a full copy.
Blockchain Trilemma: The structural trade-off in distributed networks: you can engineer hard for decentralization, security, and speed, but the third has to give. Bitcoin chose decentralization and security; most altcoins chose speed and one of the other two.

C

Cantillon Effect: The observation that newly created money doesn't enter the economy evenly. It benefits those who receive it first (banks, governments, large institutions) while diluting the purchasing power of those who receive it last (ordinary workers and savers).
Capital Controls: Government restrictions preventing citizens from moving money out of the country. Used in countries experiencing currency collapse.
Censorship Resistance: The property of a system that prevents any single party from blocking or reversing transactions. Bitcoin achieves this through decentralization.
Censorship-Resistant: A system that cannot be controlled, blocked, or censored by any central authority.
Central Bank: A national institution like the Federal Reserve that controls a country's money supply and sets interest rates. Central banks can create new money without limit.
CEO (Chief Executive Officer): The head of a company or project with decision-making authority. Bitcoin has no CEO; most altcoins do.
Chainalysis: The largest blockchain analytics firm. Their annual and mid-year Crypto Crime reports are the most-cited source for illicit cryptocurrency volume; their tracing tools are widely used by law enforcement.
Clearinghouse: A financial institution that sits between buyers and sellers to facilitate the settlement of transactions. Bitcoin eliminates the need for clearinghouses by using a decentralized network instead.
Cold Wallet (Cold Storage): Bitcoin held using keys stored offline, typically on a hardware wallet. The private key never touches an internet-connected device.
Collaborative Custody: A wallet design (used by Bitkey, Casa, Unchained) where multiple keys are required to move funds, with at least one held by a third party. Easier recovery than pure self-custody, but the third party is one of the parties capable of signing.
Consensus: Agreement among network participants about which transactions are valid and in what order they occurred. Bitcoin achieves consensus through proof of work: no voting, no authority, just math.
Consumer Price Index (CPI): The government's primary measure of inflation, tracking price changes in a basket of goods and services. Critics argue its methodology has been adjusted over decades to understate actual inflation experienced by consumers.
Cryptocurrency: A digital currency using cryptography for security. The term encompasses Bitcoin and roughly 20 million altcoins, the vast majority of which are no longer actively traded.
Currency Collapse: Rapid loss of currency value, usually due to hyperinflation or loss of confidence in a government.
Custody: Who holds the private keys. Self-custody means you do; exchange custody means a third party does.
Custody Spectrum: A ranking of the major Bitcoin holding configurations from most counterparty risk (exchange) to least (multisig). "Better" means "fewer people between you and your bitcoin."
Cypherpunks: Cryptographers and privacy advocates who believed freedom could be protected through code. They laid the intellectual groundwork for Bitcoin.

D

DCA (Dollar-Cost Averaging): Buying a fixed dollar amount of bitcoin at regular intervals regardless of price. Removes emotional decision-making and smooths out volatility over time.
Decentralization: The distribution of power across many independent participants rather than concentrating it in a single entity. Bitcoin is decentralized: no single company, server, or person controls the network.
Decentralized: Controlled by many independent parties rather than one central authority. The honest definition describes who actually holds the network's veto power. For Bitcoin, the thousands of independent node operators.
Deflation: A decrease in the general price level, meaning your money buys more over time. This happens naturally when productivity increases faster than the money supply.
Difficulty Adjustment: Bitcoin's built-in mechanism that automatically recalibrates how hard the mining puzzle is every 2,016 blocks (~2 weeks). If more miners join, it gets harder; if miners leave, it gets easier. This keeps new blocks arriving roughly every 10 minutes no matter what.
Digital Scarcity: The ability to create something digital that cannot be copied or duplicated. Before Bitcoin, this didn't exist. Bitcoin's 21 million supply cap is the first example of true digital scarcity.
Dollar-Cost Averaging (DCA): Buying a fixed dollar amount of bitcoin at regular intervals regardless of price. Smooths volatility, removes emotion, and outperforms most attempts to time the market.
Double Coincidence of Wants: The problem in barter where both parties must want exactly what the other has at the same time and place. Money solves this by acting as a universal intermediary.
Double-Spend Problem: The risk that a digital token could be spent twice, sent to two different people. Banks solve this by keeping a central ledger. Bitcoin solves it with a decentralized network of nodes that collectively verify every transaction.
Double-Spending Problem: The core challenge of digital currency: preventing someone from spending the same digital coin twice. Bitcoin solved this through consensus.

E

Emergencies Act: A Canadian federal law invoked for the first time in February 2022 during the trucker protests, granting the government extraordinary powers, including the ability to freeze bank accounts without a court order. A federal court later ruled the invocation unconstitutional.
ETF (Exchange-Traded Fund): A regulated investment product that trades on a stock exchange. Spot Bitcoin ETFs (approved January 2024) hold actual Bitcoin and let investors gain exposure through normal brokerage accounts.
ETF (Spot Bitcoin): A regulated financial product that lets investors buy shares representing bitcoin held by a custodian. The share is a securities claim on bitcoin, not bitcoin itself. ~85% of ETF-held bitcoin sits at Coinbase.
Ethereum: The largest smart-contract platform; second-largest crypto by market cap. Launched in 2015 with about 72 million ETH created in advance: 60 million sold in a presale and 12 million kept for the Ethereum Foundation and early contributors. Has revised its monetary policy four times and shipped roughly 15 protocol upgrades since launch.
Exchange: A platform where bitcoin is bought and sold for traditional currency. An on-ramp, not a vault; withdraw to your own wallet the same day you buy.

F

Fair Launch: A cryptocurrency launch where the creator owns no initial allocation and must buy it on the open market like everyone else. Only Bitcoin had a true fair launch.
Federal Reserve: The central bank of the United States, created in 1913. It controls the money supply and sets interest rates. Its ability to create new dollars is the mechanism through which inflation occurs.
Fee: A small amount of bitcoin paid by the sender to incentivize miners to include their transaction in a block. Fees vary based on network congestion.
Fiat Currency: Government-issued money that isn't backed by a physical commodity like gold. Its value comes from government decree and public trust. The US dollar, euro, and yen are all fiat currencies.
Financial Sovereignty: The ability to own, control, and use your money without permission from any government or institution.
Founder Exit / Rug Pull: When a cryptocurrency's creator abandons the project and cashes out, often after using their control to pump the price. Impossible with Bitcoin.

G

Genesis Block: The first block of the Bitcoin blockchain, mined by Satoshi Nakamoto on January 3, 2009. It contains the message about the 2008 bank bailout.
Geometric Weighting: A mathematical formula used in CPI calculations since 1999 that assigns more weight to cheaper items in a category, producing lower inflation readings than the older arithmetic method. Each methodological update has consistently pushed the official inflation number down.
Gold: A precious metal that served as the world's primary money for thousands of years due to its scarcity, durability, and difficulty to counterfeit. The US dollar was backed by gold until 1971.

H

Halving: A hardcoded event in Bitcoin's protocol, occurring roughly every four years, that cuts the rate of new bitcoin issuance in half. Halvings are the mechanism that drives Bitcoin's increasing scarcity over time. The next halving is scheduled for April 2028.
Hardware Wallet: A small dedicated device that stores private keys offline. Transactions are signed inside the device; the keys never touch the internet-connected machine. Examples: Foundation Passport Core, SeedSigner, Blockstream Jade, BitBox, Trezor's Bitcoin-only edition. All Bitcoin-only.
Hash: A fixed-length string of characters produced by running data through a mathematical function. Even a tiny change in the input completely changes the output. Used to link blocks together and secure the chain.
Hash Rate: The total computational work being done by Bitcoin miners worldwide, measured in hashes per second. As of April 2026, the network sits near 840 EH/s, the largest computational network in human history.
Hedonic Adjustments: A CPI method where product quality improvements are counted as price decreases, even when the actual dollar price went up. If a laptop gets a faster processor, the BLS may count it as cheaper. Critics argue this consistently understates inflation because consumers pay the higher price regardless of whether they wanted the upgrade.
Hot Wallet: A wallet that runs as software on an internet-connected device (phone or computer). Convenient for spending; vulnerable to whatever the device is vulnerable to. Examples: Blue Wallet, Cove, Sparrow.
Hyperinflation: Extreme and rapid inflation (often 50%+ per month) where currency loses value so fast daily life becomes impractical.

I

ICO (Initial Coin Offering): A fundraising method where a new cryptocurrency project sells tokens to the public. Many 2017 ICOs were scams; the practice is now heavily regulated and largely replaced by memecoin launchpads.
Immutable: Cannot be changed or reversed. Bitcoin's rules are immutable because they require global consensus; altcoins often have mutable rules controlled by developers.
Inflation: The expansion of the money supply, which results in each unit of currency buying less over time. Commonly described as "rising prices," but more accurately understood as the currency losing purchasing power.

K

Keynesian Economics: A school of economic thought advocating for government intervention, central bank management of the money supply, and moderate inflation as tools for economic stability. Named after economist John Maynard Keynes.
KYC/AML: "Know Your Customer" and "Anti-Money Laundering," regulatory requirements that force financial institutions to verify the identity of their customers and report suspicious activity. These rules also exclude hundreds of millions of people who lack the required documentation or paper trail.
KYC (Know Your Customer): Identity verification required by regulated exchanges. Government ID, proof of address, sometimes a live selfie. Required by law in most jurisdictions.

L

Ledger: A record of financial transactions. Banks maintain private ledgers. Bitcoin's ledger (the blockchain) is public, and anyone can verify any transaction.
Legal Tender: A form of money that must be accepted for payment of debts by law. El Salvador made Bitcoin legal tender in September 2021.
Lightning Network: A payment layer built on top of Bitcoin that settles small transactions instantly and for fractions of a cent. Transactions on Lightning don't touch the main blockchain until the channel is closed, which is what makes them fast and cheap. Bitcoin's main chain (Layer 1) remains the settlement layer for large transfers and final security; Lightning (Layer 2) handles everyday payments. Covered in detail in Lesson 1-7.
Litecoin: An early Bitcoin clone launched in 2011 with faster block times. Shares Bitcoin's structural makeup (proof-of-work, no premine, distributed nodes) but lacks the network effect that makes the structure matter at monetary scale.

M

M2 Money Supply: A measure of the total amount of money in circulation, including cash, checking deposits, savings accounts, and money market accounts. Used as a key indicator of how much money exists in the economy.
Medium of Exchange: One of the three functions of money. Something widely accepted in trade so people don't have to barter directly. The dollar serves this role today; Bitcoin is increasingly doing so.
Mempool: Short for "memory pool," the waiting area where valid but unconfirmed transactions sit until a miner includes them in a block.
Miner: A computer (or operator) that competes to solve the proof-of-work puzzle and add new blocks to the blockchain. Miners earn the block reward plus transaction fees.
Mining: The process by which new bitcoin is created and transactions are verified. Miners use computing power to solve mathematical puzzles, and the winner gets to add the next block and earn new bitcoin as a reward.
Money: A tool that solves the barter problem by serving as a medium of exchange, store of value, and unit of account. Good money is scarce, durable, divisible, portable, and widely accepted.
Money Supply: The total amount of money in circulation in an economy. When the money supply grows faster than the production of goods and services, inflation results.
Money Transfer Service: A company (like Western Union) that facilitates remittances internationally, typically charging high fees.
Multisig (Multi-Signature): A wallet configuration requiring multiple keys to authorize a transaction (e.g., 2-of-3). Eliminates single points of failure. Used for high-value holdings and structured inheritance.

N

Network Effect: The compounding value that comes from being the asset around which the largest pool of holders, miners, exchanges, regulators, and institutions has chosen to settle. For money, network effect is what makes the asset useful as money in the first place.
Node: A computer running the Bitcoin software that independently stores, verifies, and relays the full history of the blockchain. Every node checks every transaction against the rules, which is what makes Bitcoin decentralized: no single computer is in charge, because all of them are.
Nodes: Computers running Bitcoin software that validate transactions and maintain a copy of the entire blockchain. Anyone can run a node. The more nodes, the more decentralized and resilient the network.
Nominal Returns: Investment returns measured in raw dollar terms, with no adjustment for inflation. The number on the statement gets bigger every year, but the ruler used to measure it shrinks. Nominal returns flatter the chart and obscure whether your purchasing power actually grew.
Not Your Keys, Not Your Coins: Andreas Antonopoulos's mantra. If you don't control the private keys, the bitcoin isn't really yours; it's an IOU from whoever does. The structural objection to leaving bitcoin on an exchange.

O

On-Chain: A transaction recorded directly on the Bitcoin blockchain. Final, permanent, and globally verified. Takes approximately 10 minutes per confirmation. Fees vary with network demand.

P

Peer-to-Peer (P2P): A system where two parties transact directly with each other, without a middleman. Bitcoin is peer-to-peer: you send value directly to another person, verified by the network instead of a bank.
Permissionless: A system that anyone can use without requiring approval. Bitcoin is permissionless: you need only a phone and internet, not a bank account or ID.
Phishing: A social-engineering attack that impersonates a legitimate service to trick you into revealing your seed phrase, password, or one-time codes. The single most common way bitcoin is stolen.
Ponzi Scheme: A specific kind of financial fraud: a central operator promises returns paid out of new investor inflows rather than productive activity, with opaque accounting and structural collapse when inflows stop. Defined by the U.S. SEC. Bitcoin meets none of these criteria.
Premine: Coins created by the developer before public launch and allocated to insiders. Bitcoin had zero premine; most altcoins allocate 30–70% to the team, foundation, and venture-capital backers.
Private Key: A secret number that proves ownership of bitcoin and authorizes transactions. Think of it as the password to your money. Anyone who has your private key controls your bitcoin. Never share it.
Proof-of-Stake: A consensus mechanism where validation power is proportional to coin ownership. You must hold and lock up the chain's native token to validate. Inverts Bitcoin's model: in PoS, owning is governing.
Proof of Work: A system where someone proves they've done computational work. Bitcoin uses it to prevent spam and secure the network against attacks.
Protocol: A set of rules that computers follow to communicate. HTTP is the protocol for web pages. SMTP is the protocol for email. Bitcoin is the protocol for transferring value without a middleman.
Pseudonymous: Using an alternate identity rather than your real name. Bitcoin addresses don't contain your name, but transactions are public. If someone links your identity to an address, they can trace your activity.
Public Key: Derived from your private key using one-way mathematics. Used to generate your Bitcoin address. Cannot be reversed to reveal your private key.
Purchasing Power: The amount of goods or services a unit of currency can buy. When inflation occurs, purchasing power decreases, and each dollar buys less than it used to.

Q

QR Code: A square barcode that encodes your Bitcoin address. Scanning it with a wallet app is the easiest way to send bitcoin to someone, no need to manually type a long address string.

R

Real Returns: Investment returns adjusted for inflation. They show how much your purchasing power actually grew, not just how much the dollar figure went up. Real returns answer the question that matters: can you buy more with what you have than you could before?
Remittances: Money sent by workers to family in another country. Global remittances exceed $650 billion annually, with ~$40 billion/year lost to fees.

S

Sat (Satoshi): The smallest unit of bitcoin: 0.00000001 BTC (one hundred-millionth). Named after Bitcoin's creator. At $100,000/BTC, one sat equals $0.001. Most everyday Bitcoin transactions are measured in sats.
Satoshi Nakamoto: The pseudonymous creator of Bitcoin. Wrote the original whitepaper (October 2008) and code, mined the first block (January 2009), and disappeared in April 2011 leaving roughly 1 million bitcoins that have not moved on-chain since.
Satoshi (sat): The smallest unit of bitcoin: 0.00000001 BTC. Named after Bitcoin's creator, Satoshi Nakamoto. You don't need to buy a whole bitcoin; you can own a few thousand sats for a few dollars.
Scarcity: A limited supply that cannot be easily increased. Bitcoin is mathematically scarce (21M cap); most fiat currencies are not (central banks can print more).
Seed Phrase: A set of 12 or 24 English words that encodes your private key. Can restore your entire wallet on any compatible device. Treat it like a vault combination: write it down, store it securely, never share it digitally.
SegWit (Segregated Witness): A backward-compatible Bitcoin upgrade activated in August 2017 that separated transaction signature data from transaction data, increasing block capacity and enabling layer-2 networks like Lightning.
Self-Custody: Holding your own Bitcoin keys rather than trusting an exchange, bank, or custodian to hold them for you. Bitcoin's censorship-resistance and permissionless properties only hold when you self-custody; otherwise you're trusting a third party, just like with a bank.
Settlement: The actual, final transfer of value between parties. In traditional banking, settlement can take days. On Bitcoin, settlement happens when a transaction is confirmed in a block, typically within minutes.
Sound Money: Money that maintains its value over time, cannot be easily debased, and treats all holders equally. Bitcoin enforces sound money principles through code.
Stablecoin: A cryptocurrency designed to maintain a fixed value relative to a reference asset (usually the U.S. dollar). The largest are Tether (USDT) and USD Coin (USDC). Stablecoins run on different rails than Bitcoin and have different traceability and freeze properties.
Stock-to-Flow: A measure of monetary hardness: the ratio of the existing supply of an asset (the "stock") to the amount produced annually (the "flow"). Higher means harder. After the April 2024 halving, Bitcoin's stock-to-flow ratio is roughly 119, surpassing gold's roughly 62.
Stock-to-Flow Ratio: A measure of scarcity: the existing supply (stock) divided by the amount produced each year (flow). A high stock-to-flow means new supply is small relative to what already exists, making the asset hard to debase. Gold's stock-to-flow sits around 60; Bitcoin's, after the April 2024 halving, is above 120 and doubles again in 2028.
Store of Value: One of the three functions of money. Something that maintains its purchasing power over time. Gold is a strong store of value; fiat currencies are weak stores of value due to inflation.
Strategic Bitcoin Reserve: A U.S. national reserve asset, established by executive order on March 6, 2025, formalizing the federal government's existing Bitcoin holdings (~328,372 BTC, mostly seized in criminal cases) with a stated policy of not selling them.
Strike: A Bitcoin and Lightning payment app available in 70+ countries. Bitcoin-only, Lightning-native, low fees. Best international on-ramp for beginners. Founded by Jack Mallers.
Substitution Effects: A CPI method that assumes consumers switch to cheaper alternatives when prices rise: beef gets expensive, so they buy chicken. Instead of tracking what things actually cost, it tracks what a cost-flexible consumer would spend, consistently producing lower inflation readings than actual prices would show.

T

Taproot: A Bitcoin upgrade activated in November 2021 that improved privacy, scripting flexibility, and signature efficiency. The third and most recent Bitcoin soft fork.
Truflation: A decentralized, real-time inflation index that tracks over 15 million items using actual retail, housing, and economic data. Provides an alternative measurement to government-reported CPI.
Trustless: Verifiable without needing to trust any specific party. A trustless system lets you confirm something is true by checking the math or the data yourself, rather than relying on a foundation, a CEO, or a regulator.
TXID (Transaction ID): A unique identifier for a Bitcoin transaction. You can paste it into a block explorer to view the transaction's status, confirmations, fees, and details.

U

Unit of Account: One of the three functions of money. A standard measurement for pricing goods and services. The dollar is the dominant unit of account in the US.
Uptime: The percentage of time a system is operational and available. Bitcoin's network has had two minor disruptions in seventeen years (August 2010 overflow bug, March 2013 fork), with no incidents since March 12, 2013.
UTXO (Unspent Transaction Output): The way bitcoin exists on the network, as individual "chunks" from previous transactions, like bills in a physical wallet. When you spend bitcoin, you consume entire UTXOs and receive change back.

V

Venture Capital (VC): Investment money provided by firms who expect equity stakes and returns. Most altcoins accepted VC funding; Bitcoin did not.

W

Wallet: Software or hardware that manages your private keys, generates addresses, builds transactions, and signs them with your key. It doesn't "store" bitcoin; it stores the keys that prove you own it.
Whitepaper: Satoshi's 9-page technical document describing Bitcoin's design. Published October 31, 2008. The founding document of Bitcoin.
Wrench Attack: A physical attack where the attacker uses force or threat of force to compel a bitcoin holder to hand over their keys. Named after an xkcd comic showing that a $5 wrench bypasses a million dollars of cryptography. 2025 was a record year, at least 25 documented incidents by mid-year.