Acetabulum

n.	1.
	1.	(Rom. Antiq.) A vinegar cup; socket of the hip bone; a measure of about one eighth of a pint, etc.
	2.	(Anat.) The bony cup which receives the head of the thigh bone.

Noun

1.

acetabulum - the cup-shaped hollow in the hipbone into which the head of the femur fits to form a ball-and-socket joint Synonyms: cotyloid cavity

cotyloid cavity, hipbone, innominate bone, socket