A blockchain is a distributed database that is used to maintain a continuously growing list of records, called blocks. Each block contains a timestamp and a link to a previous block. Blockchain technology is often used in cryptocurrency systems such as Bitcoin and Ethereum.
Proof-of-stake (PoS) is a type of consensus algorithm that requires users to stake their cryptocurrency in order to validate transactions and add new blocks to the blockchain. The staking process requires users to lock up their cryptocurrency in a wallet for a period of time. The longer the stake, the greater the likelihood of validating a transaction and receiving a reward.