FL or variations may refer to:

Businesses and organizations

* FL, IATA code of

Fly Lili Fly Lili is a Romanian airline based at Aurel Vlaicu International Airport in Bucharest. History In April 2023, the company started its first regular charter flights, between Bucharest–Băneasa and Antalya. Beginning in June 2024, the compan ...

, a Romanian airline * FL, then-IATA code of

AirTran Airways AirTran Airways was a low-cost airline in the United States that operated from 1993 until it was acquired by Southwest Airlines May 2, 2011. Headquartered in Orlando, Florida, AirTran Airways was established in 1993 as Conquest Sun Airlines b ...

, a former American airline *

FL Group Stodir (, FL Group prior to 4 June 2008) is a majority family-owned investment company located in Reykjavík, Iceland. The company was founded on July 20, 1973, under the name Flugleiðir. It was formed as a holding company for Loftleiðir and ...

, an Icelandic investment company *

Foot Locker Foot Locker, Inc. is an American multinational retailer of footwear, sportswear, urban youth apparel and accessories headquartered in Midtown Manhattan, New York City, and operating in over 40 countries. Although established in 1974, and ...

(ticker symbol), retailer

Numismatics

Florin (disambiguation) The Florentine florin, florin was a former coin of the Republic of Florence. It may also refer to: Modern currencies * The Netherlands Antillean guilder (abbreviated ANG) is also known as a "florin", and abbreviated NAFl * Aruban florin, the curre ...

, various coins *

Guilder Guilder is the English translation of the Dutch and German ''gulden'', originally shortened from Middle High German ''guldin pfenninc'' (" gold penny"). This was the term that became current in the southern and western parts of the Holy Rom ...

, various coins also sometimes called "florin"

Places

* FL, the United States Postal Service for abbreviation for the state of

Florida Florida ( ; ) is a U.S. state, state in the Southeastern United States, Southeastern region of the United States. It borders the Gulf of Mexico to the west, Alabama to the northwest, Georgia (U.S. state), Georgia to the north, the Atlantic ...

Liechtenstein Liechtenstein (, ; ; ), officially the Principality of Liechtenstein ( ), is a Landlocked country#Doubly landlocked, doubly landlocked Swiss Standard German, German-speaking microstate in the Central European Alps, between Austria in the east ...

, as abbreviation for ''Fürstentum Liechtenstein''.

Science and technology

Biology and medicine

FLT3LG Fms-related tyrosine kinase 3 ligand (FLT3LG) is a protein which in humans is encoded by the ''FLT3LG'' gene In biology, the word gene has two meanings. The Mendelian gene is a basic unit of heredity. The molecular gene is a sequence of nuc ...

(Fms-related tyrosine kinase 3 ligand), a protein *

Fluffy transcription factor The fluffy (fl) gene of ''Neurospora crassa'' is required for asexual sporulation and encodes an 88 kDa polypeptide containing a typical fungal A fungus (: fungi , , , or ; or funguses) is any member of the group of eukaryotic organisms t ...

, gene of ''Neurospora crassa'' * Fluorouracil (5-FU), and leucovorin (folinic acid), a

chemotherapy regimen A chemotherapy regimen is a regimen for chemotherapy, defining the drugs to be used, their dosage, the frequency and duration of treatments, and other considerations. In modern oncology, many regimens combine several chemotherapy drugs in combi ...

Follicular lymphoma Follicular lymphoma (FL) is a cancer that involves certain types of white blood cells known as lymphocytes. This cancer is a form of Non-Hodgkin Lymphoma and it originates from the uncontrolled division of specific types of B-cells ( centrocytes ...

in medicine *

Frontal lobe The frontal lobe is the largest of the four major lobes of the brain in mammals, and is located at the front of each cerebral hemisphere (in front of the parietal lobe and the temporal lobe). It is parted from the parietal lobe by a Sulcus (neur ...

, the largest brain lobe

Mathematics and computing

FL (complexity) In computational complexity theory, the complexity class FL is the set of function problems which can be solved by a deterministic Turing machine in a logarithmic amount of memory space.. As in the definition of L, the machine reads its input from ...

, a class of functions *

FL (programming language) FL (short for "Function Level") is a programming language created at the IBM Almaden Research Center by John Backus, John Williams, and Edward Wimmers in the 1980s and documented in a report from 1989. FL was designed as a successor of Backus's e ...

FL Studio FL Studio (known as FruityLoops before 2003) is a digital audio workstation (DAW) developed by the Belgian company Image-Line. It features a graphical user interface with a pattern-based music sequencer. It is available in four different ...

, music production software

Other uses in science and technology

Femtolitre The litre ( Commonwealth spelling) or liter (American spelling) (SI symbols L and l, other symbol used: ℓ) is a metric unit of volume. It is equal to 1 cubic decimetre (dm3), 1000 cubic centimetres (cm3) or 0.001 cubic metres (m3). A cubic ...

, a unit of volume *

Flerovium Flerovium is a synthetic chemical element; it has symbol Fl and atomic number 114. It is an extremely radioactive, superheavy element, named after the Flerov Laboratory of Nuclear Reactions of the Joint Institute for Nuclear Research in Du ...

, symbol Fl, a chemical element (atomic number 114) *

Flight level In aviation, a flight level (FL) is an aircraft's altitude as determined by a pressure altimeter using the International Standard Atmosphere. It is expressed in hundreds of feet or metres. The altimeter setting used is the ISA sea level pressur ...

, of an aircraft * "Fluid", as in

fluid ounce A fluid ounce (abbreviated fl oz, fl. oz. or oz. fl., old forms ℥, fl ℥, f℥, ƒ ℥) is a unit of volume (also called ''capacity'') typically used for measuring liquids. The British Imperial, the United States customary, and the United S ...

(fl oz) *

Foot-lambert A foot-lambert or footlambert (fL, sometimes fl or ft-L) is a unit of luminance in United States customary units and some other unit systems. A foot-lambert equals 1/π or 0.3183 candela per square foot, or 3.426 candela per square meter (the corre ...

, a unit of luminance * Friedmann–Lemaître metric in cosmology

Sport

Federal League The Federal League of Base Ball Clubs, known simply as the Federal League, was an American professional baseball league that played its first season as a minor league in 1913 and operated as a "third major league", in competition with the e ...

, a 1914–1915 US baseball league *

English Football League The English Football League (EFL) is a league of professional association football, football clubs from England and Wales. Founded in 1888 as the Football League, it is the oldest football league in Association football around the world, the w ...

Genealogy

* ''

Floruit ''Floruit'' ( ; usually abbreviated fl. or occasionally flor.; from Latin for 'flourished') denotes a date or period during which a person was known to have been alive or active. In English, the unabbreviated word may also be used as a noun indic ...

'' (abbreviated fl.), a date when someone was active

Other uses

* , a

typographical ligature In writing and typography, a ligature occurs where two or more graphemes or letters are joined to form a single glyph. Examples are the characters and used in English and French, in which the letters and are joined for the first ligature ...

Flavius The gens Flavia was a plebeian family at ancient Rome. Its members are first mentioned during the last three centuries of the Republic. The first of the Flavii to achieve prominence was Marcus Flavius, tribune of the plebs in 327 and 323 BC; how ...

, a family or personal name in ancient Rome * Flawless, a grade of

diamond clarity Diamond clarity is the quality of diamonds that relates to the existence and visual appearance of internal characteristics of a diamond called ''inclusions'', and surface defects, called ''blemishes''. Clarity is one of the four Cs of diamond grad ...

* Fork length, a standard

fish measurement Fish measurement is the measuring of individual fish and various parts of their anatomies, for data used in many areas of ichthyology, including taxonomy and fishery biology. Overall length Standard length (SL) is the length of a fish measured ...

Free List (Liechtenstein) The Free List (, FL) is a centre-left to left-wing political party in Liechtenstein. As of 2025, it has two seats in the Landtag of Liechtenstein and is represented in five of the eleven local councils. It was founded in 1985 and described itself ...

, a political party *

Volvo FL The Volvo FL is a series of trucks manufactured by Volvo Trucks. It was introduced in 1985 and has remained in production ever since, in a variety of different models of different weight ratings. It has been used in a variety of different roles as ...

, a truck * Front Left speaker in

5.1 surround sound 5.1 surround sound ("five-point one") is the common name for surround sound audio systems. 5.1 is the most commonly used layout in home theatres. It uses five full-bandwidth channels and one low-frequency effects channel (the "point one"). Dolb ...