Acetabulum 46 is a large cavity in a bone, to receive the convex head of another, for the advantage of a circular motion. The large cavity in the os coxendix is thus named, which receives the head of the os femoris. This cavity is called the cup, from its likeness to an ancient vessel in which vinegar was brought to the table, and thence named acetabula, from acetum, vinegar, and tabula, a table. This derivation seems very probable, as which is the same measure as the ancients called acetabulum, seems to be derived from vinegar. The acetabulum, which receives the head of the thigh-bone, called also costyle, is formed by the juncture of the os ilium, ischium, and os pubis; the edge of this cavity is called supercilium, and is very prominent on the upper part; the cavity is deeper on the upper and back part than on the lower and fore part. In the natural state, this cavity is increased by an additional elastic circle, which is united to its edge; it yields easily both ways to any pressure, but recovers itself when the force is removed.,

Acetabulum also signifies a sort of glandular substance found in the placenta of some animals. See Cotyledones.

The ancient measure thus named was about the one-eighth of a pint.

Acetabulum, see Crassui.a.

Acetabulum mar. min. See Androcase.