Bitcoin Lexicon 211 terms

Short and accessible definitions of technical terms found on this site and across the Bitcoin ecosystem. Designed for newcomers : if a word in a definition is itself in the lexicon, it has its own entry.

1 Bitcoin fundamentals

Bitcoin (BTC)

Decentralised digital currency launched on 3 January 2009 by an anonymous developer (or group) using the pseudonym Satoshi Nakamoto. Bitcoin with a capital B refers to the network and protocol, bitcoin with a lowercase b refers to the unit of account.

Satoshi (sat)

The smallest unit of bitcoin. 1 BTC = 100 million satoshis. Named after the creator. In 2026, talking in sats becomes common as the price of one BTC rises.

Blockchain

A public, shared ledger that records every Bitcoin transaction in blocks linked together cryptographically. Each participant in the network keeps a copy.

Block

A group of Bitcoin transactions validated roughly every 10 minutes. Each block references the previous one, forming an unbroken chain since the Genesis block (3 January 2009).

Halving

Scheduled event every 210,000 blocks (roughly every 4 years) that cuts the miner reward in half. This mechanism makes Bitcoin issuance decline towards the total cap of 21 million.

21 million

Maximum number of bitcoins that will ever exist, hard-coded in the protocol. This programmed scarcity is a founding feature. The last sat will be mined around the year 2140.

HODL

Holding bitcoins without selling, despite the volatility. The word comes from a typo, « I AM HODLING », posted on a forum in 2013 that turned into a joke and then a mantra.

NGU

Short for « Number Go Up ». Ironic shorthand for the idea that, over the long run, the Bitcoin price tends upward.

Genesis block

The very first block mined on the Bitcoin chain, on 3 January 2009. Contains a famous message from Satoshi : « The Times 03/Jan/2009 Chancellor on brink of second bailout for banks ».

Satoshi Nakamoto

Pseudonym of the creator (or collective) behind Bitcoin. Active on forums from 2008 to 2011, then vanished without revealing any identity. Holds roughly 1.1 million BTC that have never moved.

Fiat (fiat currency)

State currency with legal tender status (euro, Swiss franc, dollar), issued by a central bank and not backed by a physical asset. By contrast, Bitcoin has an issuance capped at 21 million units, with no central issuer.

Proof of Work (PoW)

Bitcoin's consensus mechanism: miners spend energy to find a valid hash, which makes falsifying the history economically prohibitive. This work is what secures the blockchain.

Whitepaper (white paper)

Nine-page founding document published by Satoshi Nakamoto on 31 October 2008, "Bitcoin: A Peer-to-Peer Electronic Cash System". It describes how the network works, ahead of its launch in January 2009.

Altcoin (shitcoin, memecoin)

Any cryptocurrency other than Bitcoin (Ethereum, Solana, etc.). The pejorative terms shitcoin and memecoin refer to projects with no real utility or purely speculative ones.

Fork (soft fork, hard fork)

Change to the protocol rules. A soft fork stays compatible with old nodes (SegWit, Taproot); a hard fork creates a separate chain (Bitcoin Cash in 2017).

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2 Wallets, keys and addresses

Wallet

Software or device that manages your Bitcoin keys and lets you sign transactions. A wallet does not really « hold » your bitcoins, it holds the keys that prove you own them.

Private key

Secret number that proves ownership of bitcoins at a given address. Whoever holds the private key holds the bitcoins. Never share it and never store it in plain text.

Public key

Number derived mathematically from the private key, used to build a Bitcoin address. Can be shared freely.

Bitcoin address

String of characters that identifies a destination for receiving bitcoins. Four main formats, starting with 1..., 3..., bc1q... or bc1p... (Taproot, the recommended format in 2026).

Seed phrase

Sequence of 12 or 24 words (usually in English) that encodes your master key. Universal wallet backup : with these words, you can restore your funds on any compatible software.

BIP39

Standard defining the list of 2,048 words used for seed phrases. Lets every wallet brand generate seeds that are compatible with each other.

Passphrase

Extra word or phrase you add to your seed phrase to create a hidden wallet. Optional security layer, independent of the seed.

Hot wallet

Wallet connected to the Internet (mobile, desktop or online). Convenient for small amounts and fast payments, but more exposed to attacks.

Cold wallet (cold storage)

Offline wallet, with no Internet connection. Safer for storing significant amounts over the long term.

Hardware wallet

Small dedicated device (Ledger, Trezor, Coldcard, BitBox, etc.) that keeps the private key away from a potentially compromised computer. Signs transactions inside the device itself.

Multisig (multi-signature)

Configuration where a transaction must be signed by several independent keys to be valid (for example 2 of 3). Reduces the risk that a single key theft causes loss of funds.

xpub (extended public key)

Extended public key. Lets a read-only wallet see addresses and balances without being able to sign. Used for tracking and observation.

Watch-only

Mode in which a wallet observes balances and address history without holding the private key. Used to monitor a cold vault from a less secure device.

PSBT (Partially Signed Bitcoin Transaction)

Standard format (BIP 174) that lets you build a transaction on one device, sign it on another and broadcast it from a third. Backbone of the modern multisig workflow.

Custody

The custody of funds. See self-custody and custodial in the dedicated section below.

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3 Network, blocks and transactions

Node

Computer that runs the Bitcoin software and takes part in the network by validating blocks and transactions. A « full node » keeps a complete copy of the blockchain.

Bitcoin Core

Reference implementation of the Bitcoin software, written in C++ and maintained by an open-source community. This is the software that most nodes run.

Miner

Computer or farm of computers that solves the cryptographic puzzle required to add a new block to the blockchain, in exchange for a bitcoin reward.

Mining

Process of validating blocks through proof of work. Consumes electricity by design : that is what secures the network.

Mempool

Waiting area where Bitcoin transactions sit before being included in a block. The fuller the mempool, the higher the fees required.

UTXO (Unspent Transaction Output)

« Chunk » of bitcoin received and not yet spent. A wallet does not have a single balance, it has a collection of UTXOs whose sum makes up the balance.

Transaction

Act of transferring bitcoins. Consumes one or more UTXOs and produces new ones. Must be signed with the owner's private key to be valid.

Transaction fees

Amount paid to miners so they include your transaction in a block. Expressed in satoshis per virtual byte (sat/vB). Varies with network congestion.

sat/vB (satoshi per vbyte)

Standard unit for expressing the Bitcoin fee rate. A typical transaction is 100 to 250 vB. At 5 sat/vB it costs 500 to 1,250 sats.

Confirmation

Inclusion of a transaction in a block. Each new block on top adds one more confirmation. 6 confirmations is the common rule of thumb for treating a transaction as final.

RBF (Replace-By-Fee)

Mechanism that lets you replace an unconfirmed transaction with a new one carrying higher fees, in order to speed it up.

CPFP (Child Pays For Parent)

Alternative to RBF where a high-fee child transaction pulls its stuck parent out of the mempool.

Reorg (reorganisation)

Rare event in which a longer chain replaces the most recent blocks. Affected transactions have to be re-mined. This is why you wait for several confirmations.

L1 (Layer 1)

Base layer of Bitcoin, that is, the blockchain itself. Every transaction is recorded there permanently.

L2 (Layer 2)

Layer built on top of Bitcoin to handle faster or cheaper payments without recording every move on chain. Lightning Network is the main example.

Sidechain

Independent parallel chain linked to Bitcoin through a peg-in / peg-out mechanism. Liquid Network is the main Bitcoin sidechain.

Taproot

Major Bitcoin upgrade activated in November 2021 (BIP 341). Brings more privacy, scripting flexibility and the efficiency of Schnorr signatures.

SegWit (Segregated Witness)

Upgrade activated in 2017 that separates signature data from the rest of the transaction. Lowered fees and paved the way for Lightning Network.

BIP (Bitcoin Improvement Proposal)

Standard document that describes a proposed improvement to the Bitcoin protocol. Numbered (BIP 32, BIP 39, BIP 174, and so on). Open, public process on GitHub.

Hashrate

Total computing power deployed by miners, measured in hashes per second (EH/s, exahashes). The higher the hashrate, the more expensive the network is to attack.

Difficulty adjustment

Automatic recalibration every 2016 blocks (about 2 weeks) to keep one block every 10 minutes on average, whatever the current hashrate.

Consolidation (UTXO batching)

Merging several small UTXOs into one during a low-fee period, to avoid paying dearly when spending them later. A common wallet management practice.

Opcode

Elementary instruction of the Bitcoin script language (OP_CHECKSIG, OP_RETURN...). Scripts combine opcodes to define the spending conditions of funds.

Tapscript

Script language introduced by Taproot (BIP 342), an extended version of Bitcoin script with new opcodes. Technical basis of recent uses, from native multisigs to inscriptions.

MAST (Merkleized Alternative Script Trees)

Structure introduced with Taproot: several spending conditions for the same UTXO, organised as a tree. Only the branch actually used is revealed on-chain, the rest stays private.

Covenant (CTV, OP_CHECKTEMPLATEVERIFY)

Programmable restriction on how bitcoins may be spent in the future. Proposals like CTV (BIP 119) would open the way to vaults and improved channels; the community debate is ongoing.

Ordinals (inscriptions)

Protocol (2023) that numbers each satoshi and allows inscribing data (images, text) directly on-chain via Tapscript. At the origin of the debate on block space usage.

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4 Lightning and second layer

Lightning Network

Second-layer payment network on top of Bitcoin. Enables near-instant and near-free payments through channels opened between users.

Lightning channel

2-of-2 multisig between two participants that lets them exchange sats off-chain as many times as they like, until they close the channel and publish the final balance on Bitcoin.

Inbound liquidity

Capacity of a Lightning channel to receive payments. To get paid 100,000 sats, you need at least 100,000 sats of inbound liquidity available.

LSP (Lightning Service Provider)

Third-party service that helps open Lightning channels and manage liquidity, without holding your funds. Used by mobile wallets like Phoenix.

BOLT11

Standard format for a Lightning invoice, as a character string or QR code. An invoice is single-use, with an amount and an expiry date.

Lightning Address

Email-style address (alice@strike.me) that lets you receive Lightning payments without generating an invoice each time.

BOLT12

More modern Lightning invoice format (offer) that allows reuse and better privacy.

Watchtower

Service that monitors your Lightning node while you are offline and broadcasts a defence transaction if someone tries to close a channel with a fraudulent state.

Force close

One-sided closure of a Lightning channel by one participant. Costs more in fees and locks funds for a challenge period.

LND, Core Lightning (CLN), Eclair

Three main implementations of the Lightning protocol. LND (from Lightning Labs) is the most widely deployed.

HTLC (Hashed Time Lock Contract)

Contract locked by hash and by time, the building block of Lightning payments: it guarantees that a multi-hop payment is either delivered in full or refunded.

Splicing

Adding or removing capacity from a Lightning channel without closing it (BOLT 2 extension). Avoids closings and reopenings that are costly in on-chain fees.

LNURL

Family of standards that simplifies Lightning usage: reusable QR codes, withdrawals, authentication. Complemented by readable Lightning Addresses (user@domain).

MPP (Multi-Path Payment)

Lightning payment split across several simultaneous paths, recombined on arrival. Allows paying amounts larger than the capacity of a single channel.

Trampoline (Lightning routing)

Delegates route computation to specialised relay nodes: the mobile wallet no longer needs to know the whole network topology. Used notably by Phoenix.

Channel factory

Technique (still in research) where several users share the same UTXO to open many Lightning channels off-chain, reducing the on-chain footprint.

Submarine swap

Atomic exchange between on-chain funds and Lightning funds (and back), trustless, via a provider like Boltz or Lightning Loop. Used to refill or drain channels.

SCB (Static Channel Backup)

Static backup of Lightning channels (LND). If the node crashes, it allows requesting the cooperative closing of channels and recovering the funds.

eCash (Cashu, Fedimint)

Bearer tokens backed by Bitcoin, issued by a mint (Cashu) or a federation (Fedimint). Maximum privacy, but trust in the issuer; a complement to Lightning.

Peg-in, peg-out

Transfer of BTC to a sidechain (peg-in, e.g. BTC to L-BTC on Liquid) and the reverse operation (peg-out). On Liquid, the operation is signed by the federation.

Federation (sidechain)

Group of entities (exchanges, companies) that co-sign the operations of a sidechain like Liquid. A trust model halfway between a single company and Bitcoin.

Drivechains (BIP 300/301)

Proposal by Paul Sztorc: sidechains without a federation, secured by the Bitcoin miners themselves. Highly debated in the community.

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5 Custody

Self-custody

Model in which you hold your own private keys. Your bitcoins depend on no third party. This is Bitcoin's founding promise.

Custodial

Model in which a third party (exchange, broker, neobank) holds your private keys for you. You have a claim, not a bitcoin. « Not your keys, not your coins ».

Non-custodial

Common synonym for self-custody in marketing communications.

Cold storage

Storing bitcoins on an offline wallet that is not connected to the Internet. Maximum security for amounts you are not spending.

Vault

Custody setup for long-term storage, often multisig, kept offline and touched rarely.

KYC (Know Your Customer)

Mandatory identification procedure that regulated platforms apply to their users : ID document, proof of address, and so on.

AML (Anti-Money Laundering)

Set of rules to fight money laundering. KYC is the first building block. Frames what exchanges can or cannot let you do.

Exchange

Service that lets you buy, sell and swap cryptocurrencies against fiat money. Examples : Kraken, Coinbase, Bitstamp, Bitvavo. Most are custodial.

Broker

Intermediary that sells bitcoins to an end customer at a fixed price, with no visible order book. Coinhouse, Bull Bitcoin and Pocket Bitcoin are brokers.

OTC (Over The Counter)

Large-size trade executed off the order book, between two parties via a broker. Typically used for volumes above 100,000 EUR.

P2P (peer-to-peer)

Direct exchange between two people, with no centralised platform in between. Bisq, HodlHodl and AgoraDesk are P2P platforms.

Bitcoin ATM (BTM)

Automated teller machine where you can buy (and sometimes sell) bitcoin against cash. Often subject to KYC from 1,000 EUR upwards.

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6 Buying, markets, platforms

Spot

Cash price, immediate transaction at a given quote. Opposite of derivatives (futures, options).

Bitcoin spot ETF

Exchange-traded fund that holds real bitcoins, with shares tracking the price. IBIT (BlackRock) and FBTC (Fidelity) are the main ones, launched in January 2024.

ETN (Exchange Traded Note)

European / Swiss equivalent of an ETF. Structured note backed by physical bitcoin. Several ETNs have been listed in Switzerland since 2018.

Limit order

Buy or sell order executed only if the market reaches a specific price. Gives you control over the price, at the cost of execution uncertainty.

Market order

Order executed immediately at the best available price. Fast, but exposed to slippage.

Slippage

Difference between the expected price and the actual execution price. More pronounced on large orders or thinly traded markets.

Spread

Gap between the buy and sell prices displayed on a platform. The market maker's implicit margin.

Liquidity

Ability of a market to absorb an order without moving the price. Kraken and Coinbase are very liquid, a small regional platform far less so.

Trading fees

Commission charged on every trade on a platform, typically 0.1 to 1 percent depending on volume and maker / taker status.

Bisq, HodlHodl, AgoraDesk

No-KYC P2P platforms where you buy bitcoin directly from another individual via multisig escrow.

Stablecoin

Crypto pegged to a fiat currency (USDT, USDC, EURI) or to a basket of assets, designed to stay stable around 1 USD or 1 EUR.

SEPA (Single Euro Payments Area)

Single euro payments area: standardised bank transfers, free or nearly so, within one business day (a few seconds for the instant version). The cheapest deposit method on European exchanges.

ETP (Exchange Traded Product)

Family of exchange-listed products tracking an asset: ETF, ETN, ETC. In Europe, most listed Bitcoin products are legally ETNs backed by physical BTC.

Futures (futures contracts)

Standardised contracts to buy or sell BTC at a future date. Basis of the first ETFs (2021); contango (futures price above spot) erodes their performance compared with spot ETFs.

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7 Investment strategies

DCA (Dollar Cost Averaging)

Buying a small fixed amount at regular intervals (for example 100 EUR a week), regardless of price. Smooths the average purchase cost and neutralises timing bias.

Lump-sum

Investing all available capital at once rather than spreading it out. Mathematically better on average historically on Bitcoin, but psychologically harder to bear.

Value Averaging

Variant of DCA where the amount invested varies depending on whether the portfolio is below or above its target value.

Stack sats

Accumulating satoshis over time. A classic HODL mantra.

Rebalancing

Rebalancing your portfolio by selling part of what has risen and buying what has fallen, to return to a target allocation.

Drawdown

Decline from a previous peak. Bitcoin has gone through several drawdowns of more than 75 percent in its history. To factor into your psychological planning.

4-year cycle

Theory that Bitcoin follows a 4-year cycle anchored on halvings : bull market in the 18 months following a halving, then a sharp correction.

Bear market, bull market

Prolonged falling market (bear) or rising market (bull). Bitcoin cycles have historically alternated between the two around halvings, with 70 to 85 percent drops in bear markets.

Capitulation

Final phase of a bear market where the last sellers give in to panic, often on record volume. Frequently marks the cycle bottom.

ATH (All-Time High)

Highest historical price of an asset. Breaking the previous ATH is a strong psychological signal in Bitcoin cycles.

FOMO (Fear Of Missing Out)

Fear of missing the rally, which pushes people to buy at the worst moment, near the tops. DCA is the classic antidote.

S2F (stock-to-flow)

Valuation model comparing existing stock with annual production, popularised by PlanB. Appealing to illustrate Bitcoin's growing scarcity, but empirically contested.

Staking

Locking tokens to secure a proof-of-stake blockchain in exchange for a yield. Does not exist on Bitcoin, which relies on proof of work; tax-wise, staking income follows its own rules.

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8 Taxation and regulation

PFU (Prélèvement Forfaitaire Unique)

French 30 percent tax on capital gains, including crypto gains. Also called the « flat tax ». Made up of 12.8 percent income tax and 17.2 percent social levies.

Cerfa 2086

French tax form (Cerfa) used to declare crypto capital gains.

3916-bis

French tax form used to declare crypto accounts held abroad. Omitting it is fined at 750 EUR per undeclared account.

PMPA (Prix Moyen Pondéré d'Acquisition)

French method for calculating crypto capital gains : a single weighted average purchase price over the entire portfolio, recomputed at each new buy.

FIFO (First In First Out)

Capital gains method that treats the first bitcoins bought as the first sold. Used in Germany, Italy and the United States.

§23 EStG (Spekulationsfrist)

German tax provision that fully exempts Bitcoin capital gains after a holding period of more than 12 months.

Cripto-attività

Italian legal term (law 197/2022) for crypto assets, taxed at a 26 percent flat rate above an annual threshold of 2,000 EUR.

Quadro RT, Quadro RW

Sections of the Italian tax return covering crypto capital gains (RT) and holdings of foreign accounts (RW).

MiCA (Markets in Crypto-Assets)

European regulation 2023/1114 that frames crypto services across the EU since 2024. Creates the CASP status.

CASP (Crypto-Asset Service Provider)

Crypto service provider authorised under MiCA. Must obtain a licence in its home country, valid throughout the EU.

DAC8

European directive that requires crypto platforms to share tax data on their users with European tax administrations. Applicable from 2026.

TFR (Transfer of Funds Regulation)

European regulation that requires exchanges to share information on sender and beneficiary for crypto transfers above 1,000 EUR.

FINMA

Swiss Financial Market Supervisory Authority. Frames crypto activities in Switzerland.

AFC (Administration Fédérale des Contributions)

Swiss federal tax administration, which sets the criteria for crypto wealth and professional income.

IRS

United States tax administration. For US expatriates, crypto reporting to the IRS remains mandatory even outside the US.

Capital gain, capital loss

Gain (or loss) realised when disposing of an asset: the difference between sale price and acquisition cost. Tax treatment varies by country; losses can often be offset against gains of the same year.

Exit tax

Taxation of unrealised gains when transferring tax residence out of a country. France and Germany apply forms of it; a departure should be planned with a tax adviser.

LIFO (Last In First Out)

Capital gains calculation method: the last units bought are deemed sold first. Italy uses it for crypto, unlike the French weighted average cost or FIFO.

PSAN (French crypto registration)

French mandatory registration status with the AMF for crypto platforms. Progressively replaced by the European CASP authorisation under MiCA.

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9 Security and threats

2FA (Two-Factor Authentication)

Two-factor authentication. On top of the password, a second element is required to sign in (TOTP code, SMS, physical key). Standard on every serious platform.

TOTP (Time-based One-Time Password)

Six-digit code that changes every 30 seconds, produced by a dedicated app (Aegis, Raivo, Google Authenticator). Preferred 2FA method over SMS.

Phishing

Attack where someone impersonates a legitimate service via email, SMS or clone website, in order to extract your credentials or your seed phrase.

SIM swap

Attack where a fraudster convinces your phone carrier to transfer your number onto their own SIM card. They then receive your 2FA SMS messages and can take over your accounts.

Keylogger

Malicious software that records every keystroke. A seed phrase typed on an infected machine is compromised.

Malware

Umbrella term for any malicious software (virus, trojan, keylogger, ransomware, and so on).

Clipboard hijacker

Malware that monitors the clipboard and swaps a copied Bitcoin address for the attacker's own at paste time.

Dust attack

Sending a tiny amount of bitcoin (dust) to your address to try to de-anonymise your other UTXOs by analysing future spending.

Brute-force

Trying every possible combination of a password or passphrase. Ineffective against a long random password, viable against a short one.

Seed splitting (SSS, Shamir's Secret Sharing)

Technique for splitting a seed phrase into several shares (for example 3 shares of which 2 are enough to reconstruct it) and storing them in different places.

Time-lock

Time lock that prevents a transaction from being spent before a given date or block. Used for inheritance or assisted recovery.

OPSEC (operational security)

Discipline of not exposing exploitable information: not revealing holdings, separating identities and addresses, limiting metadata. A bitcoin holder's first line of defence.

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10 Cryptography

Asymmetric cryptography

System in which a private key and a public key form a pair. The public key encrypts or verifies, the private key decrypts or signs. The foundation of Bitcoin.

Hash

Function that turns data of any size into a fixed-size fingerprint. The same input always yields the same output, but you cannot go back from output to input.

SHA-256

Hash algorithm used by Bitcoin for proof of work and block hashing. Produces a 256-bit fingerprint (64 hexadecimal characters).

ECDSA

Legacy signature algorithm used by Bitcoin before Taproot. Signs a transaction with a private key to prove ownership.

Schnorr

More modern signature algorithm, activated by Taproot in 2021 (BIP 340). More efficient, enables signature aggregation (MuSig2).

MuSig2

Schnorr signature aggregation protocol (BIP 327). Lets multiple signers produce a single signature indistinguishable from a single-signer one.

secp256k1

Mathematical elliptic curve used by Bitcoin to generate private / public key pairs. Different from SHA-3 / Keccak (Ethereum).

libsecp256k1

Reference cryptographic library for Bitcoin, written in C and maintained by the Bitcoin Core developers. Used by almost every serious wallet.

CoinJoin

Transaction-mixing technique where several users combine their UTXOs into one large transaction, in order to break the input / output link.

PayJoin (P2EP)

Variant of CoinJoin where the recipient quietly adds one of their UTXOs as an input. Improves privacy and breaks heuristic analysis.

ZK-proof (Zero-Knowledge proof)

Cryptographic proof that shows a statement is true without revealing the underlying data. Ongoing research direction for Bitcoin (BitVM, rollups).

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11 General technology

GitHub

Web platform that hosts most of the world's open-source projects, including Bitcoin Core, electrs, BDK and LDK. Lets you read the code, browse change history and submit contributions.

Open source

Software whose source code is public and modifiable by anyone. A fundamental auditability guarantee in Bitcoin.

Repo (repository)

Code repository on GitHub or an equivalent platform. The Bitcoin Core repo is github.com/bitcoin/bitcoin.

Commit

Time-stamped, signed record of a code change in a Git repository. Provides history and traceability.

API (Application Programming Interface)

Interface that lets one program query another program or service. mempool.space exposes a public API for querying the chain.

RPC (Remote Procedure Call)

Standard protocol for calling functions on a remote program. Bitcoin Core exposes more than 200 RPC commands.

JSON

Structured text data format (key : value). Used everywhere for web APIs and Bitcoin RPCs.

ZMQ (ZeroMQ)

Library that lets programs exchange messages in real time. Bitcoin Core uses it to notify new transactions and new blocks.

PostgreSQL

Open-source relational database system, one of the most widely used in the world. Direct competitor to MySQL / MariaDB.

MariaDB

Database used by CapBitcoin, an open-source fork of MySQL. Functionally very close.

PHP

Server-side programming language used by CapBitcoin. Runs on most shared hosting providers.

Docker

Technology that packages an application and its dependencies into an isolated container that can be started with one command on any system.

Docker Compose

Tool that orchestrates several linked Docker containers (for example Bitcoin Core + electrs + BTCPay) through a YAML file.

VPS (Virtual Private Server)

Virtual server rented from a hosting provider (Hetzner, DigitalOcean, OVH), accessed via SSH. Typical price 5 to 30 EUR per month.

SSH (Secure Shell)

Protocol for connecting to a remote server's command line in an encrypted way.

SSL / TLS

Protocols that encrypt communications between your browser and a website. They are what makes the padlock and the https:// appear.

Metadata

Data that describes other data. For a Bitcoin transaction : size, fees, type. For an email : sender, date, subject, without the content itself.

Shutdown

Deliberate stopping of a service or device. In Bitcoin, the term is often used for the Samourai Wallet shutdown in 2024 or Blockfolio in 2022 : abrupt end of a service.

Webhook

URL called automatically by a service when an event occurs (for example, a confirmed transaction). Lets you automate reactions.

CSV

Plain-text file format where values are separated by commas. Standard for exchange history exports imported into a tax tool.

QR code

Two-dimensional barcode, ubiquitous in Bitcoin: addresses, Lightning invoices, payment URIs. Always check the decoded amount and address before confirming.

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12 Hardware and setups

Raspberry Pi

Small credit-card-sized computer at a low price (60 to 100 EUR). Lets you run a Bitcoin node at home.

RaspiBlitz

Ready-made software distribution that turns a Raspberry Pi into a Bitcoin and Lightning node. A pioneer of the genre, with an active German-speaking community.

Umbrel

Equivalent distribution for mini-PCs or Raspberry Pi, with a polished web interface and an app store (BTCPay, mempool.space, Sparrow Server, and so on).

Start9 (StartOS)

Umbrel alternative focused on sovereignty and privacy. More technically demanding, more rigorous on privacy.

MyNode

Another full-stack node distribution, with a commercial model and a paid Premium tier.

Mini-PC (NUC)

Small fanless computer such as Intel NUC, Beelink or Minisforum. More powerful than a Raspberry Pi, ideal for a serious node running Lightning and BTCPay.

Ledger, Trezor, Coldcard, BitBox

Main hardware wallet brands. Ledger Nano S Plus / X (French, the best-seller), Trezor Model T (Czech, open source), Coldcard Mk4 (Canadian, ultra-secure, Bitcoin-only), BitBox02 (Swiss, open source).

Air-gapped

Device fully disconnected from the Internet (not even USB). Top security level for signing a multisig transaction in a cold wallet.

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13 Culture, actors, events

Bitcoiner

Person interested in Bitcoin, who holds some and adheres more or less to its values (individual sovereignty, sound money, decentralisation).

Maximalist

Bitcoiner who considers that Bitcoin alone is legitimate among cryptos, and that the others (Ethereum, Solana, and so on) are distractions or scams.

Bitcoin Pizza Day

22 May. Anniversary of the first documented commercial transaction : Laszlo Hanyecz paid 10,000 BTC for 2 pizzas on 22 May 2010.

Don't trust, verify

Bitcoiner mantra. Trust no one (bank, government, exchange, influencer), verify on your own through your own node.

Not your keys, not your coins

Mantra. If you do not hold the private keys to your bitcoins, you do not truly own them. Echoes of FTX, Mt. Gox, Celsius, and others.

Be your own bank

Mantra that sums up the promise of self-custody : becoming your own bank, with no intermediary.

Time preference

Economic concept adopted by bitcoiners. A low preference for the present (the ability to defer) makes saving in bitcoin easier.

₿ (U+20BF)

Official Unicode symbol for Bitcoin, added in 2017. Like € for the euro or $ for the dollar.

Orange (#F7931A)

Official Bitcoin colour code, already present in Satoshi's original logo.

Laser eyes

2021 Twitter trend where bitcoiners added laser eyes to their profile picture to signal their conviction that BTC would reach 100,000 USD.

mempool.space

Reference open-source Bitcoin explorer in 2026. Visualisation of blocks, fees and the mempool. Launched by Wiz and the mempool.space team.

Mt. Gox

Former Japanese exchange that lost 850,000 BTC in 2014. Textbook case of custodial risk. Partial creditor compensation has been under way since 2024.

FTX

Centralised exchange that collapsed spectacularly in November 2022. Sam Bankman-Fried was convicted. Dragged Blockfolio and many funds down with it.

Samourai Wallet

Privacy-focused wallet shut down under US regulatory pressure in April 2024. A heavy blow for mainstream Bitcoin privacy.

BlackRock

World's largest asset manager. Launched its Bitcoin spot ETF IBIT in January 2024, which accumulated more than 500,000 BTC in 2 years.

MicroStrategy (Strategy)

US company led by Michael Saylor, which has made bitcoin its main treasury asset since 2020. More than 400,000 BTC accumulated by 2025.

Strategic Bitcoin Reserve (SBR)

United States strategic Bitcoin reserve created by executive order of Donald Trump in March 2025. Built from seized bitcoins.

El Salvador

First country to adopt Bitcoin as legal tender, in September 2021 under Nayib Bukele. Its status was amended in 2025 under IMF pressure.

Lugano (Plan ₿)

Swiss city that launched a Bitcoin adoption programme in 2022 (tax payments, shops, events). The annual Plan B Forum has become a European fixture.

BTC Prague

Biggest European Bitcoin conference, held every summer in Prague since 2023. A showcase for the ecosystem.

Bitcoin Beach

Nickname for El Zonte in El Salvador, the first 100 percent Bitcoin monetary community (2019). Inspired the 2021 Bitcoin law.

Cypherpunk

Movement born in the 1980s-90s advocating privacy protection through cryptography. Bitcoin is its direct heir: Satoshi announced the project on a mailing list descended from this movement.

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