Definitions
1.VerbTo set a flow of fluid or gas running by rotating a tap or valve. .mw-parser-output .defdate{font-size:smaller}"Turn on the tap/faucet."
2.VerbTo 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.; Please turn on automatic updates.; He'll turn on the charm if he thinks he's losing the sale."
3.VerbTo start operating; to power up, to become on."My computer won't turn on."
4.VerbTo 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.; Attractive showroom models can turn buyers on.; Hearing that song turned me on to jazz fusion."
5.VerbTo sexually arouse."John's a maid fetishist. Maid outfits really turn him on."
6.VerbTo take drugs.
7.VerbTo cause to take up drugs, especially hallucinogens.
8.VerbTo aim at."He turned the searchlight on the passing planes.; Cornered by the authorities, the shooter turned the gun on himself."
9.VerbTo rebel against; to suddenly attack."Suddenly all his friends turned on him."
10.VerbTo cause (someone) to rebel against or suddenly attack (someone else).
11.VerbTo 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."