locate is a Unix utility which serves to find files on filesystems.
It searches through a prebuilt database of files generated by the updatedb command or by a daemon and compressed using incremental encoding.
It operates significantly faster than find, but requires regular updating of the database.
This sacrifices overall efficiency (because of the regular interrogation of filesystems even when no user needs information) and absolute accuracy (since the database does not update in real time) for significant speed improvements, particularly on very large filesystems.
[1] The BSD and GNU Findutils versions derive from the original implementation.