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: Webster's Revised Unabridged Dictionary (1913)