sialolith: a stone formed in the salivary gland
calculus: a hard lump produced by the concretion of mineral salts; found in hollow organs or ducts of the body
quantum chromodynamics: a theory of strong interactions between elementary particles (including the interaction that binds protons and neutrons in the nucleus); it assumes that strongly interacting particles (hadrons) are made of quarks and that gluons bind the quarks together