crest

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A usually ornamental tuft, ridge, or similar projection on the head of a bird or other animal.
• noun An elevated, irregularly toothed ridge on the stigmas of certain flowers.
• noun A ridge or an appendage on a plant part, such as on a leaf or petal.
• noun A plume used as decoration on top of a helmet.
• noun A helmet.
• noun Heraldry A device placed above the shield on a coat of arms.
• noun A representation of such a device.
• noun The top, as of a hill or wave.
• noun The highest or culminating point; the peak.
• noun The ridge on a roof.
• intransitive verb To decorate or furnish with a crest.
• intransitive verb To reach the crest of.
• intransitive verb To form into a crest or crests.
• intransitive verb To reach a crest.

from The Century Dictionary.

• To furnish with a crest; serve as a crest for; surmount as a crest.
• To mark with waving lines like the plumes of a helmet; adorn as with a plume or crest.
• To reach, as a wave, the highest point; culminate.
• noun A tuft or other natural process growing upon the top of an animal's head, as the comb of a cock, a swelling on the head of a serpent, etc. See crista.
• noun Anything resembling, suggestive of, or occupying the same relative position as a crest.
• noun In heraldry, a part of an achievement borne outside of and above the escutcheon. There are sometimes two crests, which are borne on the sides. When the crest is not specially mentioned as emerging from a coronet, chapeau, or the like, it is assumed to be borne upon a wreath. A crest is not properly borne by a woman, or by a city or other corporate body, as it is always assumed to be the ornament worn upon the helmet.
• noun The foamy, feather-like top of a wave.
• noun The highest part or summit of a hill or mountain-range.
• noun In fortification, the top line of a slope.
• noun In architecture, any ornamental finishing of stone, terra-cotta, metal, or wood, which surmounts a wall, roof-ridge, screen, canopy, or other similar part of a building—whether a battlement, open carved work, or other enrichment; the coping on the parapet of a medieval building; a cresting (which see). The name is also sometimes given to the finials of gables and pinnacles.
• noun In anatomy, specifically, a ridge on a bone: as, the occipital crest; the frontal crest; the tibial crest. See phrases below, and crista.
• noun In zoology, any elongate elevation occupying the highest part of a surface. Specifically— A longitudinal central elevation, with an irregular or tuberculose summit, on the prothorax of an insect, especially of a grasshopper. A longitudinal elevated tuft of hairs or scales on the head, thorax, or abdominal segments of a lepidopterous insect.
• noun In botany: An elevated line, ridge, or lamina on the surface or at the summit of an organ, especially if resembling the crest of a helmet. An appendage to the upper surface of the leaves of curtain Hepaticæ, which in different genera has the form of a wing, a fold, or a pouch.
• noun The rising part or the ridge of the neck of a horse or a dog.
• noun Figuratively, pride; high spirit; courage; daring.
• noun See dicrotic.
• noun In ornithology, a crest of feathers rising from the front or forehead. Such crests are among the most elegant which birds possess. The cedar-bird or Carolina waxwing and the cardinal red-bird exhibit such crests. They are often recurved, as in the plumed quail of the genus Lophortyx.
• noun A transverse ridge on the hinder part of the skull of some animals, separating the occipital portion from the parietal or vertical portion.
• noun In ornithology, a tuft of feathers growing from the hindhead.

from the GNU version of the Collaborative International Dictionary of English.

• intransitive verb To form a crest.
• transitive verb To furnish with, or surmount as, a crest; to serve as a crest for.
• transitive verb To mark with lines or streaks, like, or regarded as like, waving plumes.
• noun A tuft, or other excrescence or natural ornament, growing on an animal's head; the comb of a cock; the swelling on the head of a serpent; the lengthened feathers of the crown or nape of bird, etc.
• noun The plume of feathers, or other decoration, worn on a helmet; the distinctive ornament of a helmet, indicating the rank of the wearer; hence, also, the helmet.
• noun (Her.) A bearing worn, not upon the shield, but usually above it, or separately as an ornament for plate, liveries, and the like. It is a relic of the ancient cognizance. See Cognizance, 4.
• noun The upper curve of a horse's neck.
• noun The ridge or top of a wave.
• noun The summit of a hill or mountain ridge.
• noun The helm or head, as typical of a high spirit; pride; courage.
• noun (Arch.) The ornamental finishing which surmounts the ridge of a roof, canopy, etc.
• noun (Engin.) The top line of a slope or embankment.