Protium can be any of several things: In physics and chemistry, protium refers to hydrogen-1, the most common isotope of the element hydrogen, with one proton and no neutrons. In biology, protium refers to a genus of chiefly tropical American trees in the family Burseraceae, having fragrant wood. In computer science, Protium's a universal, symbolic programming language system. In medicine, Protium's a commercial name for pantoprazole, a proton inhibitor drug.… (More on Protium)