The term crest can refer to various anatomical features.
A part of a bone:
Sagittal crest
Cnemial crest
Iliac crest
Frontal crest
Infratemporal crest
Anterior lacrimal crest
Posterior lacrimal crest
A feature on various animals:
Crest (feathers)
Display feature or thermoregulatory feature in various reptiles
Sail (anatomy) - also known as crest in some animals
The point of a horse's neck where the mane grows from
Neural crest