Meaning of “top” - Learner’s Dictionary

top

adjective [ always before noun ] us uk /tɒp/
He works at one of the country's top medical institutions.What are the odds of winning the top prizes?Domingo was Italy's top scorer.He's produced some of the top Broadway shows.He is among the top five tennis players in the country.
BEST

B1 the best, most important, or most successful:

He's one of the country's top athletes.
HIGHEST

B1 at the highest part of something:

I can't reach the top shelf.
I had to undo the top button of my jeans.

(Definition of “top adjective” from the Cambridge Learner’s Dictionary © Cambridge University Press)