L1, L01, L.1, L 1 or L-1 may refer to: Mathematics, science and technology Math L1 distance in mathematics, used in taxicab geometry L1, the space of Lebesgue integrable functions ℓ1, the space of absolutely convergent sequences Science L1 family, a protein family of cell adhesion molecules L1 (protein), a cell adhesion molecule , Lagrangian point 1, the most intuitive position for an object to be gravitationally stationary relative to two larger objects (such as a satellite with respect to the Earth and Moon) Anthranilic acid, also called vitamin L1 The first lumbar vertebra of the vertebral column in human anatomy The first larval stage in the Caenorhabditis elegans worm development Technology L1, one of the frequencies used by GPS systems (see GPS frequencies) L1, the common name for the Soviet space effort known formally as Soyuz 7K-L1, designed to launch men from the Earth to circle the Moon without going into lunar orbit ISO/IEC 8859-1 (Latin-1), an 8-bit character encoding An L-carrier cable system developed by AT&T The level-1 CPU cache in a computer Sony Xperia L1, an Android smartphone A class of FM broadcast station in North America Transportation and military Lehrgeschwader 1, from its historic Geschwaderkennung code with the Luftwaffe in World War II Lufthansa Systems' IATA code Lawrance L-1, a predecessor of the 1920s American Lawrance J-1 aircraft engine Inner West Light Rail, a light rail service in Sydney, Australia, numbered L1 L1 (New York City bus), a temporary bus route in New York City Volkswagen L1, a Volkswagen concept hybrid car L1A1 Self-Loading Rifle Locomotives Erie L-1, an American 0-8-8-0 steam locomotive class GCR Class 1B, latterly known as LNER Class L1, a class of British 2-6-4T steam locomotives GNR Class L1, latterly known as LNER Class R1, a class of British 0-8-2T steam locomotives LNER Thompson Class L1, a class of British 2-6-4T steam locomotives NCC Class L1, a Northern Counties Committee 0-6-0 class steam locomotive Pennsylvania Railroad class L1s, an American 2-8-2 steam locomotive class Soo Line L-1 class, an American 2-8-2 steam locomotive class SP&S Class L-1, an American 4-4-0 steam locomotive class SR L1 class, a class of 4-4-0 steam locomotives of Great Britain VR Class Vr1 (originally L1), a Finnish steam locomotive class Aircraft Arado L 1, a 1929 German two-seat parasol-wing sporting monoplane Macchi L.1, a 1915 Austro-Hungarian reconnaissance flying boat Stinson L-1 Vigilant, the US Army Air Forces