Blockchain and cryptocurrency
A block is a record of new transactions in the language of cryptocurrency. The moment a block is completed it’s added to the chain, creating a chain of blocks: a blockchain. Cryptocurrencies are encrypted and processing any transactions means solving complicated math problems (and these problems become more difficult over time as the blockchain grows). The ones who solve these equations are rewarded with cryptocurrency in a process called “mining.”
By saying that you own a cryptocurrency, what you actually have is the private key ( a long password, basically) to its address on the blockchain. With this key, you are entitled to withdraw currency to spend, but if you lose the key there’s no way to get your money back. Each account also has a public key, which lets other people send cryptocurrency to your account.
Information on the blockchain is also available publicly. It’s decentralized, that is, it doesn’t rely on a single computer or server to function. So any transactions are instantly visible to everyone.