timer

noun6

1. •
   Agent noun of time: someone or something that times.
2. •
   A device used to measure amounts of time.

   • start the timer when you hear the gunshot
3. •
   Any electronic function that causes a device to be able to do something automatically after a preset amount of time.
4. •
   A person who records the time elapsed in a sporting event.
5. •
   [in compounds] One who has done something a certain number of times.
6. •
   [in compounds] One characterized by a certain time or time frame, such as their work hours.