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 Advanced Telescope for High-ENergy Astrophysics (''Athena'') is an X-ray observatory mission selected by European Space Agency (ESA) within its Cosmic Vision program to address the Hot and Energetic Universe scientific theme. ''Athena'' will o ...

, a proposed X-ray telescope

Biology

Haplogroup L2 (mtDNA) Haplogroup L2 is a Human mitochondrial DNA haplogroup, human mitochondrial DNA (mtDNA) haplogroup with a widespread modern distribution, particularly in Subequatorial Africa. Its L2a subclade is a somewhat frequent and widely distributed mtDNA cl ...

in human genetics * ATC code L02 ''Endocrine therapy'', a subgroup of the Anatomical Therapeutic Chemical Classification System * the second

lumbar vertebrae The lumbar vertebrae are located between the thoracic vertebrae and pelvis. They form the lower part of the back in humans, and the tail end of the back in quadrupeds. In humans, there are five lumbar vertebrae. The term is used to describe t ...

of the vertebral column in human anatomy * the second larval stage in the ''

Caenorhabditis elegans ''Caenorhabditis elegans'' () is a free-living transparent nematode about 1 mm in length that lives in temperate soil environments. It is the type species of its genus. The name is a Hybrid word, blend of the Greek ''caeno-'' (recent), ''r ...

'' worm development

Computing

L2 cache A CPU cache is a hardware cache used by the central processing unit (CPU) of a computer to reduce the average cost (time or energy) to access data from the main memory. A cache is a smaller, faster memory, located closer to a processor core, which ...

, the Level-2 CPU cache in a computer * Layer 2 of the

OSI model The Open Systems Interconnection (OSI) model is a reference model developed by the International Organization for Standardization (ISO) that "provides a common basis for the coordination of standards development for the purpose of systems inter ...

, 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 ISO/IEC 8859-2:1999, ''Information technology — 8-bit single-byte coded graphic character sets — Part 2: Latin alphabet No. 2'', is part of the ISO/IEC 8859 series of ASCII-based standard character encodings, first edition published in 1987. I ...

(Latin-2), an 8-bit character encoding

Entertainment

* L2 (music group), an American pop duo * '' L2: Empuraan'', a 2025 Indian film, also called ''L2E'' ** ''L2: Empuraan '' (soundtrack), soundtrack album to ''L2: Empuraan'' * '' Leprechaun 2'', a 1994 American film * ''

Lineage II ''Lineage II'' is a massively multiplayer online role-playing game (MMORPG) for Windows and the second game in the ''Lineage'' series. It is a prequel to '' Lineage'' and is set 150 years before the first game. It has become popular since its Oc ...

'', a 2003 MMO game * '' Lumines II'', a 2006 puzzle game

Mathematics

* The ''L''² space of square-integrable functions * ''L''² norm * The ℓ² space of square-summable sequences * ''L''² cohomology, a cohomology theory for smooth non-compact manifolds with Riemannian metric * , the family of 2-dimensional

projective special linear group In mathematics, especially in the group theoretic area of algebra, the projective linear group (also known as the projective general linear group or PGL) is the induced action of the general linear group of a vector space ''V'' on the associa ...

s on finite fields. *

Ridge regression Ridge regression (also known as Tikhonov regularization, named for Andrey Tikhonov) is a method of estimating the coefficients of multiple- regression models in scenarios where the independent variables are highly correlated. It has been used in m ...

, regression and regularization method also known as L2 regularization

Technology and weapons

* a variety of

low-alloy special purpose steel Low-alloy special purpose steel is a grade of tool steel characterized by its proportion of iron to other elements, the kind of elements in its composition, and its treatment during the manufacturing process. The three ASTM established grades of lo ...

* a

L-carrier The L-carrier system was one of a series of carrier systems developed by AT&T for high-capacity transmission for long-distance communications. It was the first designed to handle hundreds of Voice frequency, voice frequency telephone lines, compared ...

cable system developed by AT&T * a series of fragmentation

hand grenade A grenade is a small explosive weapon typically thrown by hand (also called hand grenade), but can also refer to a Shell (projectile), shell (explosive projectile) shot from the muzzle of a rifle (as a rifle grenade) or a grenade launcher. A mod ...

s 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 The Sterling submachine gun is a British submachine gun (SMG). It was tested by the British Army in 1944–1945, but did not start to replace the Sten until 1953. A successful and reliable design, it remained standard issue in the British Army ...

in the British armed forces * a frequency used in GPS satellite navigation signals, see

GPS signals GPS signals are broadcast by Global Positioning System satellites to enable satellite navigation. Using these signals, receivers on or near the Earth's surface can determine their Position, Velocity and Time (PVT). The GPS satellite constellati ...

, a newer version is the L2C frequency

Transportation

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 Lynden Air Cargo is an American cargo airline based in Anchorage, Alaska. It operates scheduled services and on demand charter, international and domestic flights, including services for the US military. Its main base is Ted Stevens Anchorage Inte ...

, 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 The CBD and South East Light Rail is a pair of Light rail in Sydney, light rail lines running between Sydney CBD, Sydney's central business district (CBD) and the Eastern Suburbs (Sydney), south-eastern suburbs of Sydney, New South Wales, Austr ...

in Sydney, Australia, numbered L2 * L2, an S-Bahn line of the

Léman Express The Léman Express is a commuter rail network for the transborder agglomeration of Grand Genève (''Greater Geneva'') in west Switzerland and the French Alps (Haute-Savoie and Ain). Six lines serve Swiss and French towns along 230 km of ra ...

in Switzerland and France

Other uses

Second language A second language (L2) is a language spoken in addition to one's first language (L1). A second language may be a neighbouring language, another language of the speaker's home country, or a foreign language. A speaker's dominant language, which ...

(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 Ligue 2 (, League 2), also known as Ligue 2 BKT due to sponsorship reasons, is a French professional football league. The league serves as the second division of French football and is one of two divisions making up the Ligue de Football Prof ...

, a French association football league * L2 Inc, an American market research company