noun.
[capitalized] A genus of calcareous green algæ, Chlorophyceæ, found in tropical or subtropical waters: characterized by anerectaxis surmounted by a solid cap which consists of numerous radiating chambers. Also Acetabularia.
noun.
In Roman antiquity: A vinegar-cup; a small wide-mouthed vessel of earthenware or metal, sometimes placed on the larger food-dishes, in which vinegar or other condiment was served. A dry or liquid measure, .0677 of a liter. Daremberg et Saglio. A similar cup or vessel used by jugglers in their feats.
noun.
In anatomy: The cavity of the os innominatum, or hip-bone, which receives the head of the femur; the cotyle, or cotyloid cavity, formed at the junction of the ilium, ischium, and pubis. See cuts under sacrarium, quarter, innominate. A cotyledon or lobe of the placenta of ruminating animals. In insects, the socket of the trunk in which the leg is inserted. A cup-like sucker, such as those with which the arms of the cuttlefish and other dibranchiate cephalopodous mollusks are provided. See cut under Sepia. A sessile or pedunculate sucker-like organ on the ventral surface of certain entozoa.
noun.
In botany: The cup- or saucer-like fructification of many lichens. The receptacle of certain fungi.
noun.
In music, an ancient instrument, made either of earthenware or of metal, used like a kettledrum or struck against another acetabulum after the manner of cymbals.