A movement is the complete mechanism of a watch, residing within the case. It can be made up of many parts, depending on how complicated the watch is, whether it is a mechanical or electronic movement, and other factors.

Some watchmakers create their own movements in-house, while others buy in movements from companies that make them.

Sometimes a watchmaker may buy an uncompleted movement, and then do some more work on it to finish it up, perhaps by adding an escapement, a timing system, or other components. Such uncompleted movements are known as ebauches. The word ‘ebauche‘ is of French origin, meaning ‘outline’, or ‘blank’.

Movements of a particular type by a particular manufacturer are given the collective term ‘caliber’. This word is perhaps derived from the Latin expression, qua libra, meaning ‘of what weight’.