altcoin: a shortened version of “Bitcoin alternative” that applies to the number of digital coins in circulation, many of them forks of Bitcoin with minor changes to the proof of work
block: a file of data recorded on the blockchain network that includes the record of some or all new blockchain transactions. New blocks are secured to the rest of the chain via cryptography, and none can be altered without changing the rest of the chain.
blockchain: a decentralized, digital ledger of records that cannot be changed without the consensus of the majority of participants. Transactions are recorded and time-stamped in “blocks” that are linked together with cryptography.
cryptocurrencies: currencies based on blockchain that use cryptography and a decentralized system to corroborate and verify transactions
Dapp (decentralized application): a decentralized, open-source, autonomous application, with all records stored on a blockchain. It can distribute tokens.
Ethereum: an open-source software platform that uses blockchain technology to enable developers to write smart contracts and build and deploy Dapps
fiat currency: physical money, such as paper bills or coins
fork: the splitting of a blockchain into two simultaneous versions that share blocks. The community decides which version to use, and the discarded version becomes an orphan.
hard fork: a change to the rules of a blockchain that requires all users to adapt to the change
initial coin offering (ICO): crowdfunding through blockchain, with ideas, individuals, and projects looking for support by distributing coins or tokens
intermediary: a person or organization that takes part in the transaction process but is not the seller or buyer
mining: the process through which miners on a decentralized network add blocks to a blockchain
node: a computer on a blockchain network that stores a copy of the ledger
private key: a randomly generated number that a user of a cryptocurrency wallet needs to make transactions over the blockchain
security: a financial asset, usually in the form of a stock or bond that can be traded
smart contract: a protocol that can verify and enforce the terms of a contract without third parties
soft fork: a change to the rules of a blockchain that only invalidates old blocks
token: exchangeable digital assets that are typically based on blockchain. They can be used to pay participants for helping a blockchain function.