SL1 may refer to: Nortel Meridian, originally the SL-1, a private branch exchange SL-1, a former nuclear reactor in Idaho SL1 RNA, a gene family Canon EOS 100D, known as the Canon EOS Rebel SL1, a digital single-lens reflex camera Saturn SL1, a compact car that is part of the Saturn S-Series SL1 (MBTA bus), a bus route in Boston London Buses route SL1, an express bus route in London SL1, a mathematical group, see