Astacus n 1: type genus of the family Astacidae; Old World crayfish [syn: {Astacus}, {genus Astacus}]
Astacus \As"ta*cus\, n. [L. astacus a crab, Gr. ?.] (Zool.) A genus of crustaceans, containing the crawfish of fresh-water lobster of Europe, and allied species of western North America. See {Crawfish}. [1913 Webster]