Main Entry: ¹sphe·noid

Pronunciation: \ˈsfē-ˌnȯid\

Variant(s): or sphe·noi·dal \sfē-ˈnȯid-^əl\

Function: adjective

: of, relating to, or being a compound bone of the base of the cranium of various vertebrates formed by the fusion of several bony elements with the basisphenoid and in humans consisting of a median body from whose sides extend a pair of broad curved winglike expansions in front of which is another pair of much smaller triangular lateral processes while ventrally two large deeply cleft processes extend downward—see greater wing, lesser wing