Definition of crests:
(n) :
The summit of a hill or mountain ridge.
(n) :
The ridge or top of a wave.
(n) :
A tuft, or other natural ornament, growing on an animal's head, for example the comb of a cockerel, the swelling on the head of a snake, the lengthened feathers of the crown or nape of bird, etc.
(n) :
The plume of feathers, or other decoration, worn on or displayed on a helmet; the distinctive ornament of a helmet.
(n) :
(heraldry) A bearing worn, not upon the shield, but usually on a helmet above it, sometimes (as for clerics) separately above the shield or separately as a mark for plate, in letterheads, and the like.
(n) :
The helm or head, as typical of a high spirit; pride; courage.