1. timer, timepiece, timekeeper, horologe

usage: a timepiece that measures a time interval and signals its end

2. timekeeper, timer, official

usage: (sports) an official who keeps track of the time elapsed

3. timer, governor, regulator

usage: a regulator that activates or deactivates a mechanism at set times

WordNet 3.0 Copyright © 2006 by Princeton University.
All rights reserved.

See also: timer (Dictionary)