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ethmoid bone

n.
  1. A light spongy bone located between the eye sockets, forming part of the walls and septum of the superior nasal cavity, and containing perforations for the passage of olfactory nerve fibers.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.