Staking consists in holding part of your cryptoassets in a DeFi protocol, in exchange for a certain percentage return. It's a way of earning interest on your cryptocurrencies, without selling them. This system is akin to savings, with more attractive return prospects.
Staking is derived from the Proof-of-Stake consensus mechanism on which certain blockchains such as Ethereum are based. Staking your cryptocurrencies helps to secure the network.
To find out more, read our article What is staking?