chief alkaloid of opium, 1828, from French morphine or German Morphin (1816), name coined by German apothecary Friedrich Sertürner (1783-1840) in reference to Latin Morpheus, Ovid's name for the god of dreams, from Greek morphe "form, shape, beauty, outward appearance," perhaps from PIE *merph-, a possible Greek root meaning "form," of unknown origin. So called because of the drug's sleep-inducing properties.