Blockchain Terminology: A Glossary for Beginners

Definition
51% Attack
When more than 50% of the miners in a blockchain launch an attack on the rest of the nodes/users to attempt to steal assets or double spend.
Address
Much like a URL, a blockchain address is the location to or from which transactions occur on the blockchain.
Alt-coin
Any coin or token other than Bitcoin.
ASIC
A specialized computer used for specific purposes such as blockchain transactions where tailored calculations for consensus algorithms are required.
Attestation Ledger
A register or account book created for the purpose of providing support/evidence of individual transactions. Normally, an attestation ledger is used to verify that a transaction has been carried out, or to verify the authenticity of products ortransactions.
Bitcoin
The first and most popular cryptocurrency based on DLT technology developed from a whitepaper written by Satoshi Nakamoto in 2008.
Block
A group of transactions entered into a blockchain; analogous to a page of a ledger or record book.
Blockchain
A mathematical structure for storing digital transactions or data in an immutable, distributed, decentralized digital ledger consisting of blocks that are linked via cryptographic signature that is nearly impossible to fake, hack or disrupt.
Blockchain (Private a.k.a. Permissioned)
A blockchain that resides on a private network of computers that is only accessible to those with permission.
Blockchain (Public a.ka. Permissionless)
A blockchain that resides on a network of computers around the world that is accessible to everyone.
Byzantine Fault Tolerance (BFT)
A property of a distributed, decentralized system to resist complete failure even when some of the nodes fail or act maliciously.
Centralized
A system or process for which there is a singular (i.e., central) source of authority, control and/or truth.
Chain of Custody
The entire chain of documentation of ownership of a product during its lifecycle from raw materials to the final end user.
Chaincode
Another name for a smart contract.
Coin
The digital asset generated from their own blockchain representing value. For example in the Bitcoin blockchain, bitcoin is the digital asset generated used as the medium for exchange.
Consensus Algorithm
A protocol used to ensure that all nodes in a blockchain network agree on the validity of transactions and the state of the ledger.
Consensus Mechanism - Proof of Authority (PoA)
PoA is an alternative form to the PoS algorithm. Instead of staking cryptocurrency (wealth), in PoA you stake your identity. This means voluntarily disclosing who you are in exchange for the right to validate blocks. Any malicious actions you undertake as a validator will reflect back on your identity. PoA blockchains require a thorough form of KYC (Know Your Customer - a verification process that determines you actually are who you claim to be).
Consensus Mechanism - Proof of Burn (PoB)
PoB allows the miners to “burn” or destroy cryptocurrency which grants them the right to add blocks in proportion to the coins destroyed. Essentially, miners burn coins/tokens to buy virtual mining rigs that give them the power to mine blocks. The more currency burned by the miner, the bigger the ensuing virtual mining rig. To burn, miners send currency to a verifiably unspendable address. This process does not consume many resources, thus PoB is often called PoW without energy waste. Depending upon the implementation, miners are allowed to burn the native currency or the currency of an alternative chain, and in exchange, they receive a reward in the native currency of the blockchain.
Consensus Mechanism - Proof of Capacity (PoC)
PoC allows the mining devices in the network to use their available hard drive space to decide the mining rights, instead of using the mining device’s computing power (as in PoW) or the miner’s stake in the cryptocurrency (as in PoS).
Consensus Mechanism - Proof of Stake (PoS)
In PoS, miners put up(i.e., “stake”) some of the blockchain’s cryptocurrency (e.g., ether for the Ethereum blockchain) in order to increase their chances of being selected to validate a block. The stake is locked up as a deposit to ensure the miner validates the block according to the rules. If the miner violates the rules, the deposit will be “burned” or destroyed. PoS is less resource intensive than PoW since fewer miners are racing to solve the mathematical formula.
Consensus Mechanism - Proof of Work (PoW)
In PoW, transaction data (block) + a random strings of digits (nonce of block) are repeatedly applied to a (hashing)mathematical formula by miners, until a desirable outcome is found (the proof of work). Other miners then verify the proof of work by taking the alleged input string and applying it to thesame formula to see if the outcome is indeed that what was presented. If the results are the same, the transaction is verified and added to the blockchain. As many miners are racing to solve the formula which requires a great deal of computing power, PoW is resource intensive.
Consensus Mechanism (a.k.a. Consensus Protocol)
The process used to validate a transaction across a distributed blockchain network designed to achieve Byzantine Fault Tolerance.
Cryptocurrency
Digital money which uses encryption and consensus algorithms to regulate the generation of coins/tokens and transfer of funds. Cryptocurrencies are generally decentralized, operating independently of central authorities.
Cryptography
The science of securing communication using individualized codes so only the participating parties can read the messages.
DAO (Decentralized Autonomous Organization)
A governance structure without a central authority which rewards good behavior and penalizes bad behavior by a set of pre-defined rules which can only be changes by a vote, which typically requires a stake, adding risk to the processto discourage bad actors, amongst the participants.
DApp
Software which does not rely on a central system or database but can share information amongst its users via a decentralized database, such as a blockchain.
Decentralization/Decentralized
A system with no single point where the decision is made. Every node makes a decision for its own behavior and the resulting system behavior is the aggregate response.
Decentralized Domain Name System (DDNS)
A system for registering and resolving domain names on the blockchain, rather than through a centralized domain registrar.
Decentralized Identity (DID)
A DID is a unique identifier not containing any personally identifiable information. They are publicly available and owned by the person, asset, or company. (see verifiable credential) In a VC world, people, assets and organizations have a Decentralized Identifier (DID).
DeFi - Decentralized Finance
A system of financial applications and services built on blockchain technology that enables peer-to-peer transactions without the need for intermediaries.
Digital Identity (a.k.a. Self-Sovereign Identity)
The network or Internet equivalent to the real identity of a person or entity (like a business or government agency). Advocates of blockchain-based digital identity is to return ownership and control of personal information to the individuals. In any given transaction, personal information is not disclosed, but rather the information required by one party is verified by the digital identity application.
Digital Signature
A mathematical scheme for verifying digital messages or documents satisfy two requirements - they have authenticity (from a known sender) and integrity (were not altered in transit.
Digital Signature - Multi-signature
In order to increase security, multisig addresses require more than one digital signature (and therefore multiple keys) to sign a transaction or message.
Digital Signature - Ring
A digital signature that can be performed by any of a group of people that each have keys. A property of a ring signature is that it is impossible to determine which of the group signed the transaction.
Distributed
As opposed to decentralized, a distributed system shares processing and/or data across multiple nodes, but the decisions may still be centralized and use complete system knowledge.
Distributed Ledger Technology (DLT)
The larger class of technology of which blockchain is a subset. A digital system for recording the transaction of assets in which the transactions and their details are recorded in multiple identical copies at the same time with no central data store or administration.
Double Spending
A unique problem to cryptocurrency where the same coins or tokens are spent or traded twice.
Ethereum
A public blockchain that supports smart contracts.
Ethereum Name Service (ENS)
A decentralized domain name system built on the Ethereum blockchain that allows users to register and manage human-readable domain names.
Fiat
Legal tender the value for which is backed by a government or governmental body (e.g., US dollars, Euros)
Fork
A collectively agreed upon software update by all nodes in a distributed network. Sometimes, the previous version continues in parallel with the new version.
Fungible
The property an item of being exchangeable with other like items. For example, USD and Euros are fungible. The value of USD can be expressed in Euros.
Gas
A fee charged to write a transaction to a public blockchain. The gas is used to reward the miner which validates the transaction.
Genesis Block 
The first or first few blocks of a blockchain.
Governance
Establishment of policies and continuous monitoring of their proper implementation of an organization or system.
Governance Token
A type of token that grants holders the right to vote on key decisions related to the development and management of a blockchain ecosystem. Used in a DAO or DeFi projects.
GPU
Graphical processing unit (hardware) used for complex computing.
Hash Function
A function that receives an input of any size and returns a unique string of a uniform length.
Hyperledger Fabric
IBM’s private (permissioned) blockchain toolset.
Identity
The information on an entity used by computer systems to uniquely represent a person, organization, application, or device.
Immutable/Immutability
The property of being unchangeable. Once a transaction has been added to a block and written to a blockchain, it cannot be changed and therefore is immutable.
Initial Coin Offering (ICO)
The first sale of a blockchain coin or token.
Interoperability
The ability of two or more systems to communicate and exchange data. Due to various design decisions (e.g., consensus protocol) most blockchains are not interoperable, however there are many projects that are working to connect various blockchains.
IPFS (Interplanetary File System)
A peer-to-peer hypermedia protocol for storing and sharing data in a distributed file system using content-addressing to uniquely identify each file in a global namespace connecting all computing devices.
Know Your Asset (KYA)
The immutable proof of assset relation to an organization or entity.
Know Your Customer (KYC)
The legal process of a business identifying and verifying the identity of its clients. KYC requirements vary from jurisdiction to jurisdiction.
Liquidity
The ease of converting an asset (or, in this case, cryptocurrency) to cash (fiat).
Mainnet
The production version of a blockchain.
Merkle Tree/Hash Tree
In cryptography and computer science, a Merkle or hash tree is a tree in which every leaf node is labeled with the hash of a data block, and every non-leaf node is labeled with the cryptographic hash of the labels of its child nodes.
Mining
In a public blockchain, the process of verifying a transactionand writing it to the blockchain for which the successful miner is rewarded in the cryptocurrency of the blockchain.
Namecoin
A decentralized naming system that is built on top of the Bitcoin blockchain.
Node
A computer which holds a copy of the blockchain ledger.
Non-Fungible
The property an item of not being exchangeable with other like items. For example, USD and Euros are fungible. For example, a Stratovarius violin is non-fungible because the value of it cannotbe expressed in a number of other violins.
Non-Fungible Token (NFT)
A unique digital asset that is stored on a blockchain and represents ownership of a specific item, such as artwork or music.
Off-chain
Data stored external to the blockchain.
On-chain
Data stored within the blockchain.
Open Source
Software products that include permission to use, enhance, reuse or modify the source code, design documents, or content of the product.
Oracle
An application that connects blockchain applications to legacy applications.
Peer-to-Peer (P2P)
A direct connection between two participants in a system – can be computer to computer or person to person.
Plasma
A scaling solution for blockchain technology that enables fasterand more efficient transactions.
Provenance
The entire history of a product during its lifecycle including its chain of custody and all documentation of value-added services and activities which were used to produce that product or service.
Public/Private Key
A public key is a unique string of characters derived from a private key which is used to encrypt a message or data. The private key is used to decrypt the message or data.
Satoshi Nakamoto
The name used by the person or entity who developed bitcoin, authored the bitcoin white paper, and created and deployed bitcoin’s original reference implementation. As part of the implementation, Nakamoto also devised the first blockchain database.
Security Token Offering (STO)
A type of token sale that offers tokens that are backed bytangible assets, such as stocks or real estate.
Seed Phrase
A random sequence of words which can be used to restore a lost wallet.
Sharding
A type of database partitioning that separates very large databases the into smaller, faster, more easily managed parts called data shards. Sharding can potentially be used to improve blockchain performance.
Sidechain
A discrete blockchain that is linked to a main blockchain via two-way pegs which enable assets to be interchanged between the main blockchain and the sidechain. Sidechains are a method to enable scaling and increase transaction speed by only performing necessary transactions on the main blockchain.
Smart Contract
Self-executing computer code deployed on a blockchain to perform a function, often, but not always, the exchange of value between a buyer and a seller.
Solidity
A JavaScript-like object-oriented programming language for Ethereum for implementing smart contracts on the Ethereum blockchain.
Stablecoin
A cryptocurrency which is underwritten by an asset or assets (e.g., fiat currency, commodities, etc.) designed to minimize the volatility of the price of the coin/token.
State Channel
A process by which blockchain transactions are executed off- chain, collected and then written to the main chain as a single transaction in order to improve performance and reduce cost.
Testnet
A staging blockchain environment for testing application before being put into production (or onto the mainnet).
Token
Cryptographic tokens represent programmable assets or access rights, managed by a smart contract and an underlying distributed ledger. They are accessible only by the person who has the private key for that address and can only be signed using this private key.
Token Burn
The process of removing tokens from circulation in order to reduce the total token supply. Thus increasing the value of the remaining tokens in circulation.
Token Distribution
The way in which tokens are initially distributed among investors, developers, and other stakeholders such as users on the network.
Token Generation Event
The creation and first sale of a blockchain coin or token.
Token Liquidity
The ease with which tokens can be bought or sold on a market, which affects their overall value and market cap.
Token Market Cap
The total value of all tokens in circulation, calculated by multiplying the token price by the total token supply.
Token Price
As an asset, the value of a single token in a particular currency, such as but not limited to USD or BTC.
Token Sale
An event in which tokens are offered for sale to investors, often used to raise funds for a blockchain project or startup.
Token Supply
The total number of tokens that will ever be created for a particular blockchain network.
Token Type - ERC-20
A type of fungible Ethereum token (i.e., smart contract) standard which is defined by a series of functions that must be supported, including functions to retrieve the total supply, transfer from one wallet to another, and approve a transaction. Typically, any given ERC-20 token has many copies which are held in a variety of crypto wallets.
Token Type - ERC-721
A type of non-fungible Ethereum token (i.e., smart contract) standard which is defined by a series of functions that must be supported, including functions to retrieve the total supply, transfer from one wallet to another, and approve a transaction. Each ERC-721 token is unique and non-interchangeable with other tokens (i.e., non-fungible).
Token Utility
The function or purpose of a token within a blockchain network, such as providing access to certain services or products.
Token Value
The perceived worth of a token, often determined by market demand and supply.
Token Velocity
The rate at which tokens are exchanged or used within a blockchain ecosystem.
Token/Coin Exchange
An application to buy, sell and trade cryptocurrencies.
Tokenless Ledger
A ledger that doesn’t require a native currency to operate.
Tokenomics
The study, design and implementation of monetary management and distribution based on blockchain technology.
Transactions Per Second (TPS)
A measurement of the speed of a blockchain. The low TPS of most blockchains is a significant barrier to using blockchain for business, especially financial, applications.
Transparency
A primary property of public blockchains whereby any participant in a system or transaction can view the transactions on the blockchain.
Trust
Confidence in the integrity of an entity (e.g., person, organization, etc.).
Trustless
The elimination of trust from a transaction. Blockchain is called a trustless system because the two entities performing a transaction do not need to trust one another. The properties of blockchain - digital signatures, cryptography, etc. - provide the trust.
Verifiable Credential
In its simplest form, a Verifiable Credential is a document that can be reliably traced back to its source and validated as genuine.
Vyper
A Python-like programming language for the Ethereum blockchain built for security, language and compiler simplicity, and auditability.
Wallet
A digital file that holds coins and tokens held by the owner. The wallet also has a blockchain address to which transactions can be sent.
Wallet (Cold)
A wallet disconnected from the internet.
Wallet (Hot)
A wallet connected to the Internet.
Wallet (Multisignature)
A wallet that requires multiple digital signatures to execute a transaction.
Web3
Internet solutions, where blockchain technology is used to create decentralized applications and services that are more secure, transparent, and trustworthy. Web3 is a term used to describe the third generation of the World Wide Web, which is being developed to provide a more decentralized and user-centric internet experience.
Web3 Browser
A web browser that supports blockchain technology and enables users to interact with decentralized applications. Example: Brave browser.
Web3 Domain Name Registrars
A decentralized naming system used to map domain names to IP addresses on the internet.
Web3 Domain Ownership
In the context of Web3, domain ownership refers to the ownership of decentralized domain names, which are registered on the blockchain rather than with a central domain registrar. There are new domain extensions in Web3 stored on the blockchain controlled by smart contracts with no third-party intermediaries such as ICANN, including .crypto, .eth, and .nft. You can register your trademark as a web3 domain (i.e. yourcompanyname.eth). So can anyone else, including scammers, hackers, and your competitors. Web3 wallet owners hold private keys that execute software code that controls ownership. Transfers of domain names occur only when the person who owns that wallet says so.
Web3 Wallet
A digital wallet that allows users to store and manage their cryptocurrency, NFTs, and other digital assets on a blockchain network. Unlocked with a private key, controlled by the wallet owner.
Zeppelin/Open Zeppelin
A community of like-minded Smart Contract developers.
Zero Knowledge Proof
The ability to share proof of something, without disclosing details that prove this information to be true. For example proving you’re over 21 without showing your birthday.