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Meaning of top banana

top' banan'a

Pronunciation: [key]
— Slang. Slang.
  1. a leading comedian in musical comedy, burlesque, vaudeville, etc.: For many years he was top banana on the circuit.
  2. the chief person in a group or undertaking.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.