Clicker (noun)

1. A small device that makes a clicking noise when pressed, used as a signaling or counting device.
2. A remote control device used to operate electronic devices, especially television sets and VCRs.

Origin:

From the sound made by the device, a clicking noise.

Examples:

1. The dog trainer used a clicker to signal to the dog when it had performed the correct behavior.
2. The teacher used a clicker to keep track of student attendance.
3. He lost the clicker that controlled his TV and had to buy a new one.
4. The clicker is a handy device for signaling to a dog when it has performed a desired behavior.
5. She used the clicker to turn on the TV from across the room.