The process by which the state of a blockchain on a particular block height is recorded.
Snapshot refers to the process whereby the state of a blockchain of a particular block height is recorded. It is designed to be used for a specific duration of time. When not properly utilized, snapshots can lead to an excessive accumulation of data, one that tends to get mixed up and eventually becomes useless.
During airdrop events, snapshots serve as tools for recording the balance token of token holders at a particular block height. This ensures that each token holder is verified as being qualified to participate in that distribution round.
The terminology has recently adopted a broader meaning. An exchange can take a snapshot of users at a specific point to decide who gets rewards and in what proportion. A snapshot of token holders is also an important aspect of new token launches on most reliable platforms.