(noun)
a tuft or comb of skin, fur, or feathers on the top of an animal's or bird's head;
e.g. The woodpecker had a magnificent red crest on its head.
(noun)
a distinctive emblem that is featured above the shield in a coat of arms or on other materials to represent/symbolize a family or group;
e.g. The document had the family crest printed at the top.
(verb)
to reach the top of something such as a hill or mountain;
e.g. They will crest the hill and spend the night at the top.
(verb)
to have something fixed or attached to its top, or to attach something to the top of an object;
e.g. She will crest the hat with flowers and sequins.