Chronograph
Complicated watch with a function for measuring short time periods in addition to its function for permanently displaying hours, minutes and seconds.
Chronometer
Label given to a watch which has undergone precision tests and received a certificate from an official body (COSC).
Date
The day of the month, displayed in a window on a watch dial typically at the 3 o'clock or 6 o'clock position.
Small seconds
A hand on a sub-dial which tracks seconds typically it completes a full rotation in one minute.
Tachymeter
A tachymeter is an instrument for measuring speed. It is a chronograph with a graduated dial on which speed can be read off in kilometres per hour based on 1000 metres distance.