Key — a set of characters needed to access a cryptocurrency wallet. There are two types of keys. Public — also known as the address — allows anyone to view the contents of the wallet. Private — this key is necessary for spending funds from the wallet.

Pending — this is a transaction that has already entered the blockchain but has not yet been included in a block and is awaiting processing by miners.

Smart contract — this is a specific algorithm recorded in the blockchain. Smart contracts are used to perform complex operations, such as issuing tokens or exchanging assets through decentralized applications.

Transaction — an operation in the blockchain, such as transferring coins between wallets or using a smart contract.