on (Adjective) — In operation or operational. ex. "left the oven on" ex. "the switch is in the on position"
on (Adjective) — (of events) planned or scheduled. ex. "the picnic is on, rain or shine" ex. "we have nothing on for Friday night"
on (Adverb) — With a forward motion. ex. "the circus travelled on to the next city" ex. "march on"
on (Adverb) — Indicates continuity, persistence or concentration. ex. "his spirit lives on" ex. "shall I read on?"
on (Adverb) — In a state required for something to function or be effective. ex. "turn the lights on" ex. "get a load on"
on (Preposition) — At some time in the duration of. ex. "I'll come some time on Sunday"
on (Preposition) — In contact with, on top of. ex. "the book on the table"
on (Preposition) — Located at or attached to. ex. "there's a jam on the main road" ex. "the clock on the wall"
on (Preposition) — Part of; a member of. ex. "she's on the shortlist"
on (Preposition) — On the topic of. ex. "a book on physics"
on (Preposition) — Paid for by. ex. "dinner's on me" ex. "drinks are on the house"
on (Preposition) — Supported by. ex. "balanced on one leg"
on (Preposition) — At or following a prescribed point in time. ex. "The contract was rendered void on his death"
on (Preposition) — Having something. ex. "I don't have any on me"