L4 or L-4 may refer to :

Transportation

SP&S Class L-4 The Spokane, Portland and Seattle Railway (SP&S) class L-4 steam locomotives were originally used by the Astoria and Columbia River Railroad (AC&R). They became SP&S locomotives when the SP&S acquired the A&CR. Background The Astoria & Columbi ...

, an 1884 steam locomotives class * USS ''L-4'' (SS-43), a 1915 United States Navy L-class submarine * HMS ''L4'', a 1918 British L class submarine * Lawson L-4, a 1924 American unflown biplane airliner *

Piper Cub The Piper J-3 Cub is an American light aircraft that was built between 1938 and 1947 by Piper Aircraft. The aircraft has a simple, lightweight design which gives it good low-speed handling properties and short-field performance. The Cub is P ...

(U.S. military designation: L-4), an aircraft *

Inline-four engine A straight-four engine (also referred to as an inline-four engine) is a four-cylinder piston engine where cylinders are arranged in a line along a common crankshaft. The majority of automotive four-cylinder engines use a straight-four layout ( ...

(L4), a type of inline internal combustion four cylinder engine ** Liberty L-4, a World War I four-cylinder, water-cooled, inline, aero-engine * Lynx Aviation (IATA code) * L4 (New York City bus), a temporary bus route in New York City * L4, an S-Bahn line of the Léman Express in Switzerland and France * Parramatta Light Rail, also known as the L4, a light rail service in Parramatta, Sydney, Australia * Chaika L-4, a Russian twin-engined amphibious aircraft * Soviet submarine L-4

Science and technology

L4 microkernel family L4 is a family of second-generation microkernels, used to implement a variety of types of operating systems (OS), though mostly for Unix-like, ''Portable Operating System Interface'' (POSIX) compliant types. L4, like its predecessor microkernel ...

, a family of operating system kernels *L4, the transport layer in 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 ...

of computer communications * L4, the fourth

Lagrangian point In celestial mechanics, the Lagrange points (; also Lagrangian points or libration points) are points of equilibrium (mechanics), equilibrium for small-mass objects under the gravity, gravitational influence of two massive orbit, orbiting b ...

in an astronomical orbital configuration * L⁴, an L^p space for p=4 (sometimes called Lebesgue spaces) * L-4, the fourth iteration of

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 ...

, high capacity frequency division multiplex over coaxial cable used by the Bell System

Biology

Haplogroup L4 (mtDNA) Haplogroup L4 is a human mitochondrial DNA (mtDNA) haplogroup. It is a small maternal clade primarily restricted to Africa. L4 is important in East Africa. The highest frequencies are in Tanzania Tanzania, officially the United Republic o ...

, a human mitochondrial DNA haplogroup * Ribosomal protein L4, a human gene * L4, a

lumbar vertebra 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 the ...

of the vertebral column, in human anatomy * The fourth and last 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

Other uses

* L4, a modern version of the

Bren light machine gun The Bren gun (Brno-Enfield) was a series of light machine guns (LMG) made by the United Kingdom in the 1930s and used in various roles until 1992. While best known for its role as the British and Commonwealth forces' primary infantry LMG in Worl ...

in the British Army *

ISO/IEC 8859-4 ISO/IEC 8859-4:1998, ''Information technology — 8-bit single-byte coded graphic character sets — Part 4: Latin alphabet No. 4'', is part of the ISO/IEC 8859 series of ASCII-based standard character encodings, first edition published in 1988. I ...

(Latin-4), an 8-bit character encoding

Transportation

Science and technology

Biology

Other uses

See also