on

/ɒn/

#8 of the most-used English words

verb

1. To switch on
   "Can you on the light?"

Similar: turn on

adjective

1. In the state of being active, functioning or operating.
   "All the lights are on, so they must be home."
2. Performing according to schedule; taking place.
   "Are we still on for tonight?"
3. Fitted; covering; being worn.
   "I was trying to drink out of the bottle while the top was still on!"
4. (usually negative) Acceptable, appropriate.
   "You can't do that; it's just not on."

Similar: base, on, leg

adverb

1. To an operating state.
   "turn the television on"
2. So as to cover or be fitted.
   "Put on your hat and gloves."
3. Along, forwards (continuing an action).
   "drive on, rock on"
4. In continuation, at length.
   "He rambled on and on."

preposition

1. Positioned at the upper surface of, touching from above.
   "A vase of flowers stood on the table."
2. Positioned at or resting against the outer surface of; attached to.
   "He had a scar on the side of his face."
3. Expressing figurative placement or attachment.
   "All of the responsibility is on him."
4. Denoting performance or action by contact with the surface, upper part, or outside of anything; hence, by means of; with.
   "to play on a violin or piano"

Similar: by dint of, due to, about, apropos, as for