Switch

A switch is a small control for an electrical device which you use to turn the device on or off.
A device that selects the paths or
circuits to be used for transmission of information and establishes a connection;

A device for making, breaking, or changing the connections in an electrical circuit.

Sources:

Англійський словник Коллінза, електронний ресурс: https://www.collinsdictionary.com/

Nick Brieger, Alison Pohl: Technical English Vocabulary and Grammar.

Словник Webster's Dictionary https://www.merriam-webster.com/