In IT, a snapshot is a point-in-time copy of the state of a disk, virtual machine or file system that lets you roll back to that moment within seconds. Because it is usually kept on the same storage as the original data, it does not replace a backup. For example, an administrator takes a snapshot of a server before installing an update.
Go deeper on the TecnetBlog: Data Replication: A Complete Guide for Businesses
VM snapshot, storage snapshot, snapshot vs backup, disk snapshot, point-in-time copy