It was an acquaintance of Shulgin's named Humphry Osmond, a British psychiatrist and researcher into the effects of mescaline and LSD, who coined the word ''psychedelic'' in the late 1950's for a class of drugs that significantly alter one's perception of reality. Derived from Greek, the term translates as ''mind manifesting'' and is preferred by those who believe in the curative power of such chemicals. Skeptics tend to call them hallucinogens.