Meaning
To activate or start a device, light, or machine.
Example Sentence
"Please turn on the lights — it's getting dark."
Synonyms
switch on
start
activate
power up
Usage Note
This phrasal verb is separable. When using a noun object, it can go between the verb and particle or after the particle. When using a pronoun object, it must go between the verb and particle (e.g., "turn it off" not "turn off it").