adverb (or adjective)
1.
a. : in a state of accomplishment, success, or dominance
extreme reactionary … elements have come out on top — Nation
b. : in the lead
the horse went on top in the backstretch
2. also on the top Brit : in high gear
3. : above the clouds or bad weather
when flying on top, your plane is in brilliant sunshine — What Goes On Up There