a tall, cylindrical hat with a stiff brim usually slightly curved on the sides, worn by men esp. on formal occasions. Cf. beaver 1
(def. 4), opera hat, silk hat.
top-hatPronunciation: (top'hat'), [key]
of or pertaining to polite or fashionable society.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.