Light Meaning Heater Starts Operating Synonym Refrigerator Time

Meaning: If something like a light or a heater goes on, it starts operating.

• go on The light in the refrigerator isn't on all the time. It goes on when you open the door.
  
  
• go on The air conditioner goes on automatically at 7 a.m., so the office is at a comfortable temperature by the time we get there.