turn on

verb turns on · turning on · turned on

1. transitive To set a flow of fluid or gas running by rotating a tap or valve. Turn on the tap/faucet.

   Opposite: turn off

2. transitive To power up, to put into operation, to start, to activate (an appliance, light, mechanism, functionality etc.). Please turn the lights on so I can see what I'm reading.
3. intransitive, of a device To start operating; to power up, to become on. My computer won't turn on.

   Similar: turn against

4. transitive To introduce (someone to something), and especially to fill them with enthusiasm (about it); to intoxicate, give pleasure to ( + to an object of interest or excitement). Attractive packaging can turn buyers on to a product.
5. transitive To sexually arouse. John's a maid fetishist. Maid outfits really turn him on.
6. intransitive, slang To take drugs. "Well, they seem to always have dope up there, and I like to turn on, too." "You do?" "Sure. Cops is just people. I don't drink, so I gotta do something to get my kicks."
7. slang, transitive To cause to take up drugs, especially hallucinogens. In fact, many youngsters will not even turn on a close friend if they know he has never used drugs. And it is rare indeed for a youth to actively seek out people to turn on.
8. transitive To aim at. He turned the searchlight on the passing planes.
9. transitive To rebel against; to suddenly attack. Suddenly all his friends turned on him.
10. ditransitive To cause (someone) to rebel against or suddenly attack (someone else). We need to be thinking about what it means the way they are locking us up, and turning us on each other. We need to start fighting for our rights together.
11. intransitive To depend upon; to pivot around, to have as a central subject. The argument turned on the question of whether or not jobs would be lost.
12. transitive, of a railroad semaphore To lower, blocking the way and signalling that a train may not proceed.

    Opposite: turn off

Opposite: shut off, turn off