gallstone

n. abnormal stonelike mass which forms in the gallbladder

In medicine, gallstones (choleliths) are crystalline bodies formed within the body by accretion or concretion of normal or abnormal bile components.Gallstones can occur anywhere within the biliary tree, including the gallbladder and the common bile duct. Obstruction of the common bile duct is choledocholithiasis; obstruction of the biliary tree can cause jaundice; obstruction of the outlet of the pancreatic exocrine system can cause pancreatitis. Cholelithiasis is the presence of stones in the gallbladder—chole- means "gall bladder", lithia meaning "stone", and -sis means "process".
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Gallstone /gall·stone/ biliary calculus; a calculus formed in the gallbladder or bile duct. gall·stone n. [more]Gallstone - Community and Resources

Noun
1. a calculus formed in the gall bladder or its ducts
(synonym) bilestone
(hypernym) calculus, concretion

(n.)
A concretion, or calculus, formed in the gall bladder or biliary passages. See Calculus, n., 1.