The Collaborative International Dictionary of English v.0.48:
Gallstone \Gall"stone`\, n. A concretion, or calculus, formed in the gall bladder or biliary passages. See Calculus, n., 1. [1913 Webster]WordNet (r) 3.0 (2006):
gallstone n 1: a calculus formed in the gall bladder or its ducts [syn: gallstone, bilestone]