on-off device
nounUK /ˌɒn ˈɒf dɪˌvaɪs/
US /ˌɑːn ˈɔːf dɪˌvaɪs/
A thing you use to turn something on or off.
The light switch is an on-off device.
RELATED WORDS
OTHER MEANINGS
2. A device that has only two states, fully on or fully off.
The old fan has an on-off device, so it cannot run at half speed.
3. A simple control that starts or stops a machine.
Press the on-off device to stop the drill.
4. A switch that connects or cuts electrical power.
The on-off device on the power strip cuts electricity to all the plugs.