{ Xan"thine (?), n. Also Xan"thin }. [Gr. xanqo`s yellow.] (Physiol. Chem.) A white microcrystalline nitrogenous compound, C₅H₄O₂N₄, present in muscle tissue, in the liver, spleen, pancreas, and other organs, and also in urine (in small quantities) and some urinary calculi, and in the juices of certain plants; -- so called because it leaves a yellow residue when evaporated to dryness with nitric acid. Xanthine is closely related to uric acid.

{ Xan"thine (?), n. Also Xan"thin }. [Gr. xanqo`s yellow.] (Physiol. Chem.) A white microcrystalline nitrogenous compound, C₅H₄O₂N₄, present in muscle tissue, in the liver, spleen, pancreas, and other organs, and also in urine (in small quantities) and some urinary calculi, and in the juices of certain plants; -- so called because it leaves a yellow residue when evaporated to dryness with nitric acid. Xanthine is closely related to uric acid.