Definition of: hypoxanthine

(hī′pə·zan′thēn, -thin) noun Biochem.
A crystalline alkaloid, C₅H₄N₄O, found in various organs, and especially in the muscular tissue of animals, also in certain seeds. Also hy′po·xan′thin (-thin). [<Gk. hypoxanthos yellowish–brown <hypo- under + xanthos yellow]
—hy′po·xan′thic adjective