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

Example:
What is the difference between kidney stone and Gallstone? What is the difference in treatment?

Taxonomy
gallstones, gallbladder, bile duct, stones, bile, Cholesterol gallstones, patients, liver, treatment, bilirubin, gallstone disease, Gallbladder surgery, duct, laparoscopic cholecystectomy, Digestive, Gallbladder stones, cholesterol, laparoscopic gallbladder removal.

Defination from the web:
gallstones are, how they form, and how they can be treated. From the American Gastroenterological Association (AGA) patient center.