[n] the cup-shaped hollow in the hipbone into which the head of the femur fits to form a ball-and-socket joint
\Ac`e*tab"u*lum\, n. [L., a little saucer for vinegar, fr. acetum vinegar, fr. acere to be sour.]
1. (Rom. Antiq.) A vinegar cup; socket of the hip bone; a measure of about one eighth of a pint, etc.
2. (Anat.) (a) The bony cup which receives the head of the thigh bone. (b) The cavity in which the leg of an insect is inserted at its articulation with the body. (c) A sucker of the sepia or cuttlefish and related animals. (d) The large posterior sucker of the leeches. (e) One of the lobes of the placenta in ruminating animals.