Definitions for "Sub-dial"
A small dial on the face of a watch. May be used as dual time zone indicator, alarm, moonphase, chronograph, etc. Maximum of four sub-dials on a watch?s face.
Smaller dial located on the watch face or main dial used for such purposes as displaying seconds or dates. A watch can have no sub-dials or several sub-dials.
See Register above; a dial within or on the main dial of a watch.