The Collaborative International Dictionary of English v.0.48:

Timepiece \Time"piece`\, n.
   A clock, watch, or other instrument, to measure or show the
   progress of time; a chronometer.
   [1913 Webster]

WordNet (r) 3.0 (2006):

timepiece
    n 1: a measuring instrument or device for keeping time [syn:
         timepiece, timekeeper, horologe]