A timer is a device or person that keeps track of the passage of time. There are an enormous number of places in which the passage of time must be measured, and there are an enormous number of devices that do this. A timer can be one of two types: a device which counts up from zero, a device which counts down from a specific time interval. Timers can be mechanical or digital. Some timers give some specific "alarm" or indication when a specified interval has ended. Among the applications of timers are, to name a few:

• Timers to time the cooking of a boiled egg. There are sometimes just inexpensive hourglasses.
• Timers to set a limit on the length of time one is permitted to take in Scrabble and other games. There are often inexpensive hourglasses also.
• Timers used in competitive chess games. These are often quite sophisticated.
• Timers for athletic events.
• Timers to limit the time that one sleeps, that is, alarm clocks.
• Timers built in to microwave ovens.
• Timers for other things in the kitchen.
• Timers for a multitude of industrial and scientific processes.
• Timers in computer code to watch for some piece of software that is taking too long.

In ancient times hour glasses were used to measure time. Stopwatches, kitchen timers, and even phones have replaced timers in the modern world.

In a Toastmasters meeting, training people to keep their speeches close to a predetermined length is accomplished by a person who is assigned the task of "timer".

• Toastmasters.org - The official web site for Toastmasters International.
• Toastmasters Wiki