Source : Webster's Revised Unabridged Dictionary (1913)

Ethmoid \Eth"moid\, Ethmoidal \Eth*moid"al\, a. [Gr. ? like a
   sieve; ? sieve + ? from: cf. F. ethmo["i]de, ethmo["i]dal.]
   (Anat.)
   (a) Like a sieve; cribriform.
   (b) Pertaining to, or in the region of, the ethmoid bone.

   {Ethmoid bone} (Anat.), a bone of complicated structure
      through which the olfactory nerves pass out of the cranium
      and over which they are largely distributed.

Source : WordNet®

ethmoid bone
     n : one of the eight bones of the cranium; a small bone filled
         with air spaces that forms part of the eye sockets and
         the nasal cavity [syn: {ethmoid}]