Cotyloid \Cot"y*loid\ (k?t"?-loid), a. [Cotyle + -oid] (Anat.)
   (a) Shaped like a cup; as, the cotyloid cavity, which receives the head of the thigh bone.
   (b) Pertaining to a cotyloid cavity; as, the cotyloid ligament, or notch.

Source: Webster's Revised Unabridged Dictionary (1913)