Staking is locking a cryptoasset in a network or validator smart contract to earn yield (typically 3–10% APY). It is what secures a Proof-of-Stake blockchain: validators put capital at risk, and dishonest behaviour gets punished.
On TON, validators stake Gram (300,000+ GRAM per validator), and regular holders can join through nominator pools or liquid-staking protocols like Tonstakers from as little as 1 GRAM.