2. The plume of feathers, or other decoration, worn on a helmet; the distinctive ornament of a helmet, indicating the rank of the weare; hence, also, the helmet. Stooping low his lofty crest. Sir W. Scott. And on his head there stood upright A crest, in token of a knight. Gower.

3. (Her.)

Defn: 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.

4. The upper curve of a horse's neck. Throwing the base thong from his bending crest. Shak.

5. The ridge or top of wave. Like wave with crest of sparkling foam. Sir W. Scott.

6. The summit of a hill or mountain ridge.

7. The helm or head, as typical of a high spirit; pride; courage. Now the time is come That France must vail her lofty plumed crest. Shak.

8. (Arch.)

Defn: The ornamental finishing which surmounts the ridge of a roof,
canopy, etc.
The finials of gables and pinnacles are sometimes called crest.
Parker.

9. (Engin.)