1. The natural process of bone formation.
2. 1. The hardening or calcification of soft tissue into a bonelike material.
   2. A mass or deposit of such material.
3. 1. The process of becoming set in a rigidly conventional pattern, as of behavior, habits, or beliefs.
   2. Rigid, unimaginative convention.

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.