Validator stake refers to the SOL delegated to a Solana validator to increase its weight in the network's Proof of Stake consensus. Validators with more stake are selected more frequently to produce blocks and earn proportionally more rewards.

SOL holders can delegate their tokens to validators through native Solana staking (via wallet interfaces or the Solana CLI) to earn a share of block rewards — typically a few percent annually. This is distinct from DeFi application-level staking.

Validator staking is how the Solana network achieves economic security. The cost of attacking the network is proportional to the total SOL staked — a higher total stake makes attacks more expensive.