*cotyloidal*

a. [ Cotyle + -oid ] (Anat.) (a) Shaped like a cup; cup-shaped; as, the cotyloid cavity, the cup-shaped socket which receives the head of the thigh bone. (b) Pertaining to a cotyloid cavity; as, the cotyloid ligament, or notch.
Syn. -- acetabular, cotyloid. [ 1913 Webster + WordNet 1.5 ]