from The American Heritage® Dictionary of the English Language, 4th Edition
- n. A watch that can be instantly started and stopped by pushing a button and used to measure an exact duration of time.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. A timepiece designed to measure the amount of time elapsed from a particular time when activated and when the piece is deactivated.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. a timepiece that can be started or stopped for exact timing (as of a race)
stop + watch (Wiktionary)