G4 or G.IV may refer to:

Transport

AEG G.IV The AEG G.IV was a biplane bomber aircraft used in World War I by Germany. It was developed from the AEG G.III, with refinements to power, bomb-load and dimensions. Coming into service in late 1916, it featured a bomb capacity twice as large as t ...

, a German World War I heavy bomber * Allegiant Air, by IATA airline designator *

Caudron G.4 The Caudron G.4 was a French biplane with twin engines, widely used during World War I as a bomber. It was designed by René and Gaston Caudron as an improvement over their single-engined Caudron G.3. The aircraft employed wing warping for ban ...

, a 1915 French biplane *

Friedrichshafen G.IV The Friedrichshafen G.IV and G.V (factory designations FF.61 and FF.55) respectively were heavy bombers that were designed and manufactured in Germany during World War I by Flugzeugbau Friedrichshafen. The G.IV saw limited use by the ''Luftstreit ...

, a 1918 German medium bomber *

Gotha G.IV The Gotha G.IV was a heavy bomber used by the (Imperial German Air Service) during World War I. It was the first mass-produced large airplane. Development Experience with the earlier G.III showed that the rear gunner could not efficientl ...

, a 1916 German heavy bomber *

Gulfstream IV The Gulfstream IV (or G-IV or GIV) and derivatives are a family of twinjet aircraft, mainly for private or business use. They were designed and built by Gulfstream Aerospace, a General Dynamics company based in Savannah, Georgia, United States, ...

, a family of private jet aircraft * Mitsubishi G4M "Betty", a World War II Japanese fast bomber * Soko G-4 Super Galeb, a jet trainer/light attack jet of Yugoslav origin * USS ''G4'' (SS-26), a 1914 G-class submarine of the United States Navy *

County Route G4 (California) There are 21 routes assigned to the "G" zone of the California Route Marker Program, which designates county routes in California. The "G" zone includes county highways in Monterey, San Benito, San Luis Obispo, Santa Clara, and Santa Cruz cou ...

, a county highway in Santa Clara County, California, USA *

G4 Beijing–Hong Kong and Macau Expressway The Beijing–Hong Kong and Macau Expressway (), designated as G4 and commonly referred to as the Jinggang'ao Expressway () is a -long expressway that connects the Chinese cities of Beijing and Shenzhen, in Guangdong province, at the border wit ...

, an expressway in China *

G4 (Taichung Metro) Songzhu () is a railway station and metro station located in Beitun District, Taichung, Taiwan. It is served by the Taiwan Railways Administration Taichung line and the Green Line (Taichung Metro), Green Line operated by Taichung Metro, connecte ...

, also known as Songzhu Station or Jiushe Station, a station under construction in the Taichung Metro *

G4-class freighter The G4 class is a series of five combination roll-on/roll-off cargo ships (ConRO) that are operated by the Atlantic Container Line (ACL) and entered service in the mid-2010s. They are named ''Atlantic Star'', ''Atlantic Sail'', ''Atlantic Sea'', ...

, a cargo ship design

Biology

G4 EA H1N1 In virology, influenza A virus subtype H1N1 (A/H1N1) is a subtype of influenza A virus. Major outbreaks of H1N1 strains in humans include the Spanish flu, the 1977 Russian flu pandemic and the 2009 swine flu pandemic. It is an orthomyxovirus ...

, a strain of influenza *

G-quadruplex In molecular biology, G-quadruplex secondary structures (G4) are formed in nucleic acids by sequences that are rich in guanine. They are helical in shape and contain guanine tetrads that can form from one, two or four strands. The unimolecular ...

, a DNA secondary structure

Science and technology

Group 4 element Group 4 is the second group of transition metals in the periodic table. It contains the four elements titanium (Ti), zirconium (Zr), hafnium (Hf), and rutherfordium (Rf). The group is also called the titanium group or titanium family after its lig ...

, a class of elements on the Periodic Table *

ATC code G04 G04B Urologicals G04BA Acidifiers :G04BA01 Ammonium chloride :G04BA03 Calcium chloride :QG04BA90 Methionine G04BC Urinary concrement solvents :''Empty group'' G04BD Drugs for urinary frequency and incontinence :G04BD01 Emepronium :G04BD02 Fla ...

''Urologicals'', a subgroup of the Anatomical Therapeutic Chemical Classification System * G4, a type of

bi-pin lamp base A bipin or bi-pin (sometimes referred to as two-pin, bipin cap or bipin socket) is a type of lamp fitting. They are included in the IEC standard "IEC 60061 Lamp caps and holders together with gauges for the control of interchangeability and safe ...

(socket), a lamp fitting where the pin spacing is 4mm *

LG G4 The LG G4 is an Android smartphone developed by LG Electronics as part of the LG G series. Unveiled on 28 April 2015 and first released in South Korea on 29 April 2015 and widely released in June 2015, as the successor to 2014's G3. The G4 is pri ...

smartphone * Moto G4, a line of smartphones *

Group 4 compression CCITT Group 4 compression, also referred to as G4 or Modified Modified READ (MMR), is a lossless method of image compression used in Group 4 fax machines defined in the ITU-T T.6 fax standard. It is only used for bitonal (black-and-white) images. G ...

, a type of image compression used in fax machines and some image file formats

Apple Computer

* PowerPC G4, a type of microprocessor by Freescale used by Apple **

Power Mac G4 The Power Mac G4 is a series of personal computers designed, manufactured, and sold by Apple Computer from 1999 to 2004 as part of the Power Macintosh line. Built around the PowerPC G4 series of microprocessors, the Power Mac G4 was marketed by ...

, a series of personal computers made by Apple Inc in July 1999 ** PowerBook G4, a series of Professional notebooks made by Apple Inc in 2001 **

iMac G4 The iMac G4 is an all-in-one personal computer designed, manufactured, and sold by Apple Computer from January 2002 to August 2004. It replaced the iMac G3 and was succeeded by the iMac G5. Design and marketing The iMac G4 featured an L ...

, a series of personal computer made by Apple Inc in January 2002 ** Xserve G4, an

Xserve Xserve is a line of rack unit computers designed by Apple Inc. for use as servers. Introduced in 2002, it was Apple's first designated server hardware design since the Apple Network Server in 1996. In the meantime, ordinary Power Macintosh G3 a ...

server made by Apple Inc in May 2002 ** iBook G4, an iBook series of consumer notebooks in October 2003 ** Mac Mini G4, a

Mac Mini Mac Mini (stylized as Mac mini) is a small form factor (desktop and motherboard), small form factor desktop computer developed and marketed by Apple Inc. , it is positioned between the consumer all-in-one iMac (Intel-based), iMac and the profes ...

series of ultracompact computer in January 2005

Entertainment

G4 (American TV network) G4 (also known as G4TV) was an American pay television and digital network owned by Comcast Spectacor that primarily focused on video games. The network was originally owned by G4 Media, a joint venture between the NBCUniversal Cable division ...

, an American television channel *

G4 (Canadian TV channel) G4 was a Canadian English-language specialty television channel owned by Rogers Media. The name was licensed from NBCUniversal, whose parent company Comcast formerly owned a minority stake in the channel. Based on the U.S subscription networks T ...

, a former Canadian television channel *

G4 (band) G4 are a four-piece British vocal troupe who first came to prominence when they finished second in Series 1 of ''The X Factor'' in 2004, and are known for their operatic delivery of modern pop songs. Originally a barbershop quartet A barbers ...

, a British vocal troupe *

Grob's attack Grob's Attack is an unconventional chess opening in which White begins with the move: :1. g4 It is widely considered to be one of the worst possible first moves for White. International Master John Watson writes, "As far as I can tell, 1 g4 i ...

, an opening move in chess

Organisations

* G4 nations, four nations that support each other's bids to become permanent members of the United Nations Security Council: Brazil, Germany, India, and Japan * Big Four (Western Europe), sometimes called 'G4', a group of powerful countries in Europe *

VIP Protection Unit The VIP Protection Unit ( Abbreviation: VIPPU; ), otherwise known as G4 (originally Section G, Division 4) is a branch of the Hong Kong Police Force. Introduction The original name had been given to the unit since it is the 4th division of the ...