A validator is a network participant that proposes or attests to blocks in proof-of-stake systems.
Validators lock stake and earn rewards for honest duties. Offline or malicious behavior can reduce rewards or slash stake.
In research workflows, Validator is usually interpreted with Proof of stake, Staking, Slashing, and Node rather than as a standalone signal. Throughput, finality, and fee markets determine user experience and where activity migrates during congestion.