metallic element of the platinum group, 1803, coined in Modern Latin by its discoverer, English chemist Smithson Tennant (1761-1815) from Greek osmē "smell, scent, odor" good or bad, from PIE root *hed- "to smell" (see odor). With metallic element ending -ium. So called for the pungent smell of its oxide, a highly poisonous acid. The densest stable element, it commonly is found in alloy with iridium. Related: Osmic; osmious.