Morphine

Morpheus was the god of dreams, or more particularly the shapes (morphai) that come to one in dreams. Later he became confused with the god of sleep and it is from this confusion that the meaning of morphine comes. Morphine, an addictive compound of the opium plant, is used as an anaesthetic or sedative. The compounds which include the stem morph-, such as metamorphosis (a transformation into another shape or state of being), are drawn from the Greek word morphe ("shape" or "form") and not the god Morpheus.