L2

L2, L2, L02, L II, L.2 or L-2 may refer to:

Astronomy

 * L2 point, second Lagrangian point in a two body orbiting system
 * L2 Puppis, star which is also known as HD 56096
 * Advanced Telescope for High Energy Astrophysics, a proposed X-ray telescope

Biology

 * Haplogroup L2 (mtDNA) in human genetics
 * ATC code L02 Endocrine therapy, a subgroup of the Anatomical Therapeutic Chemical Classification System
 * the second lumbar vertebrae of the vertebral column in human anatomy
 * the second larval stage in the Caenorhabditis elegans worm development

Computing

 * L2 cache, the Level-2 CPU cache in a computer
 * Layer 2 of the OSI model, in computer networking
 * L2 (operating system), or Liedtke 2 (a.k.a. EUMEL/ELAN), a persistent microkernel operating system developed by German computer scientist Jochen Liedtke
 * L2 (programming language)
 * ISO/IEC 8859-2 (Latin-2), an 8-bit character encoding

Entertainment

 * L2 (music group), an American pop duo
 * L2: Empuraan, a 2024 Indian film
 * Leprechaun 2, a 1994 American film
 * Lineage II, a 2003 MMO game
 * Lumines II, a 2006 puzzle game

Mathematics

 * The L2 space of square-integrable functions
 * L2 norm
 * The ℓ2 space of square-summable sequences
 * L2 cohomology, a cohomology theory for smooth non-compact manifolds with Riemannian metric
 * $L2(n)$, the family of 2-dimensional projective special linear groups on finite fields.

Technology and weapons

 * a variety of low-alloy special purpose steel
 * a L-carrier cable system developed by AT&T
 * a series of fragmentation hand grenades used by the British armed forces (American M61 copies), before being replaced by the L109 grenade
 * the L designation given to the Sterling submachine gun in the British armed forces
 * a frequency used in GPS satellite navigation signals, see GPS signals, a newer version is the L2C frequency

Aircraft

 * LZ 18 (L 2), a short-lived 1913 German airship (Imperial Navy designation: L 2)
 * Arado L II, a 1929 German model of high-wing sporting monoplane
 * ASJA L2, a pair of 1932 Swedish trainer biplanes
 * Lawson L-2, a 1920 American biplane airliner
 * Macchi L.2, an Italian model of biplane flying boat
 * L-2 Grasshopper, an American Taylorcraft model used in WWII
 * PZL Ł.2, a 1929 Polish model of liaison aircraft

Aviation

 * Junkers L2, an engine model; precursor to the Junkers L5
 * Lynden Air Cargo, Alaskan airline (IATA code: L2)
 * Walker County Airport (or Bevill Field), Alabama, U.S. (former FAA LID: L02)

Rail locomotives

 * Chesapeake and Ohio Class L-2 and L-2a, an American 4-6-4 "Hudson" type steam locomotives model
 * Milwaukee Road class L2, an American 2-8-2 "Mikado" type steam locomotive
 * SP&S Class L-2, an 1881 steam locomotives class
 * LNER Class L2, a 1925 class of 2-6-4Ts

Other modes of transport

 * L2 (New York City bus), a temporary bus route in New York City, U.S.
 * The Randwick branch of the CBD and South East Light Rail in Sydney, Australia, numbered L2

Other uses

 * Second language (L2), a non-native, acquired tongue of an individual
 * L², a Flemish political youth organization
 * L-2 visa, a U.S. travel document for dependents of temporary workers
 * a class of FM radio broadcasting in North America
 * Ligue 2, a French association football league
 * L2 Inc, an American market research company