# L2

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> Source: https://en.wikipedia.org/wiki/L2
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**L2**, **L2**, **L02**, **L II**, **L.2** or **L-2** may refer to:

## Astronomy

- [L2 point](/source/L2_point), second Lagrangian point in a two body orbiting system
- [L2 Puppis](/source/L2_Puppis), star which is also known as HD 56096
- [Advanced Telescope for High Energy Astrophysics](/source/Advanced_Telescope_for_High_Energy_Astrophysics), a proposed X-ray telescope

## Biology

- [Haplogroup L2 (mtDNA)](/source/Haplogroup_L2_(mtDNA)) in human genetics
- [ATC code L02](/source/ATC_code_L02) *Endocrine therapy*, a subgroup of the Anatomical Therapeutic Chemical Classification System
- the second [lumbar vertebrae](/source/Lumbar_vertebrae) of the vertebral column in human anatomy
- the second larval stage in the *[Caenorhabditis elegans](/source/Caenorhabditis_elegans)* worm development

## Computing

- [L2 cache](/source/L2_cache), the Level-2 CPU cache in a computer
- Layer 2 of the [OSI model](/source/OSI_model), in computer networking
- [L2 (operating system)](/source/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)](/source/L2_(programming_language))
- [ISO/IEC 8859-2](/source/ISO/IEC_8859-2) (Latin-2), an 8-bit character encoding

## Entertainment

- [L2 (music group)](/source/L2_(music_group)), an American pop duo
- *[L2: Empuraan](/source/L2:_Empuraan)*, a 2025 Indian film, also called *L2E* - [*L2: Empuraan* (soundtrack)](/source/L2:_Empuraan_(soundtrack)), soundtrack album to *L2: Empuraan*
- *[Leprechaun 2](/source/Leprechaun_2)*, a 1994 American film
- *[Lineage II](/source/Lineage_II)*, a 2003 MMO game
- *[Lumines II](/source/Lumines_II)*, a 2006 puzzle game
- L2, a former name of the [O2 Academy Liverpool](/source/O2_Academy_Liverpool)

## Mathematics

- The [*L*2 space](/source/L2_space) of square-integrable functions
- [*L*2 norm](/source/Norm_(mathematics)#p-norm)
- The [ℓ2](/source/Hilbert_space#Sequence_spaces) space of square-summable sequences
- [*L*2 cohomology](/source/L%C2%B2_cohomology), a cohomology theory for smooth non-compact manifolds with Riemannian metric
- *L*2(*n*), the family of 2-dimensional [projective special linear groups](/source/Projective_special_linear_group) on finite fields.
- [Ridge regression](/source/Ridge_regression), regression and regularization method also known as L2 regularization

## Technology and weapons

- a variety of [low-alloy special purpose steel](/source/Low-alloy_special_purpose_steel)
- a [L-carrier](/source/L-carrier) cable system developed by AT&T
- a series of fragmentation [hand grenades](/source/Hand_grenade) used by the British armed forces (American [M61](/source/M61_grenade) copies), before being replaced by the [L109](/source/L109) grenade
- the L designation given to the [Sterling submachine gun](/source/Sterling_submachine_gun) in the British armed forces
- a frequency used in GPS satellite navigation signals, see [GPS signals](/source/GPS_signals), a newer version is the [L2C](/source/L2C) frequency

## Transportation

### Aircraft

- [LZ 18 (L 2)](/source/LZ_18_(L_2)), a short-lived 1913 German airship (Imperial Navy designation: *L 2*)
- [Arado L II](/source/Arado_L_II), a 1929 German model of high-wing sporting monoplane
- [ASJA L2](/source/ASJA_L2), a pair of 1932 Swedish trainer biplanes
- [Lawson L-2](/source/Lawson_L-2), a 1920 American biplane airliner
- [Macchi L.2](/source/Macchi_L.2), an Italian model of biplane flying boat
- [L-2 Grasshopper](/source/L-2_Grasshopper), an American Taylorcraft model used in WWII
- [PZL Ł.2](/source/PZL_%C5%81.2), a 1929 Polish model of liaison aircraft

### Aviation

- [Junkers L2](/source/Junkers_L2), an engine model; precursor to the Junkers L5
- [Lynden Air Cargo](/source/Lynden_Air_Cargo), Alaskan airline (IATA code: L2)
- [Walker County Airport](/source/Walker_County_Airport) (or *Bevill Field*), Alabama, U.S. (former FAA LID: L02)

### Rail locomotives

- [Chesapeake and Ohio Class L-2 and L-2a](/source/Chesapeake_and_Ohio_Class_L-2_and_L-2a), an American 4-6-4 "Hudson" type steam locomotives model
- [Milwaukee Road class L2](/source/Milwaukee_Road_class_L2), an American 2-8-2 "Mikado" type steam locomotive
- [SP&S Class L-2](/source/SP%26S_Class_L-2), an 1881 steam locomotives class
- [LNER Class L2](/source/LNER_Class_L2), a 1925 class of 2-6-4Ts

### Other modes of transport

- [L2 (New York City bus)](/source/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](/source/CBD_and_South_East_Light_Rail) in Sydney, Australia, numbered L2
- L2, an S-Bahn line of the [Léman Express](/source/L%C3%A9man_Express) in Switzerland and France

## Other uses

- [Second language](/source/Second_language) (L2), a non-native, acquired tongue of an individual
- L², a Flemish political youth organization
- [L-2 visa](/source/L-2_visa), a U.S. travel document for dependents of temporary workers
- a [class of FM radio broadcasting in North America](/source/List_of_North_American_broadcast_station_classes#FM)
- [Ligue 2](/source/Ligue_2), a French association football league
- [L2 Inc](/source/L2_Inc), an American market research company

## See also

- [2L (disambiguation)](/source/2L_(disambiguation))
- [LII (disambiguation)](/source/LII_(disambiguation))
- [Level 2 (disambiguation)](/source/Level_2_(disambiguation))

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Adapted from the Wikipedia article [L2](https://en.wikipedia.org/wiki/L2) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/L2?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.