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