Lysergic acid diethylamide, abbreviated LSD or LSD-25, also known as lysergide (INN) and colloquially as acid, is a semisynthetic psychedelic drug of the ergoline family, well known for its psychological effects which can include altered thinking processes, closed and open eye visuals, synesthesia, an altered sense of time and spiritual experiences, as well as for its key role in 1960s counterculture
NOT the hallucinogen LSD is an abbreviation for "Long, Slow Distance," which refers to the practice of running longer distances at an "easy" pace rather than shorter ones to exhaustion The slower pace allows the runner to go longer and, therefore (supposedly), gain more fitness