timer

noun

1. a timepiece that measures a time interval and signals its end

   noun.artifact

   Source: WordNet 3.0

2. (sports) an official who keeps track of the time elapsed

   noun.person

   Synonyms timekeeper

   Source: WordNet 3.0

3. a regulator that activates or deactivates a mechanism at set times

   noun.artifact

   Source: WordNet 3.0

4. A timekeeper; especially, a watch by which small intervals of time can be measured; a kind of stop watch. It is used for timing the speed of horses, machinery, etc.

   noun

   Source: webster1913

5. In electric ignition, an adjustable device for automatically timing the spark.

   noun

   Source: webster1913