1. Anatomy. A crest or ridge, as on the top of a bone.
2. Biology. One of the inward projections or folds of the inner membrane of a mitochondrion.

[Latin.]

The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved.