Definitions:
a comb or tuft of feathers, fur, or skin on the head of a bird or other animal

the top of a mountain or hill

the curling foamy top of a wave

a distinctive device representing a family or corporate body, borne above the shield of a coat of arms (originally as worn on a helmet) or separately reproduced, for example on writing paper.

reach the top of (a hill or wave)

(of a wave) form a curling foamy top

have attached at the top