A snapshot is a point-in-time copy of a system's state or data that can be used for backup or recovery purposes. A snapshot is not a full backup; it is a quick method to capture the current state that usually uses copy-on-write technology to minimize storage requirements. Full backups, in contrast, capture all data at one point in time, while replication involves copying data to a secondary location in real-time or near-real-time. Incremental backups are a series of backups that save changes made since the last backup, which could be either another incremental or a full backup.