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 Allegiant Air (usually shortened to Allegiant) is an ultra low-cost U.S. carrier that operates scheduled and charter flights. It is a major air carrier, the fourteenth-largest commercial airline in North America. Allegiant was founded in 1 ...

, 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, 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 The Mitsubishi G4M was a twin-engine, land-based medium bomber formerly manufactured by the Mitsubishi Aircraft Company, a part of Mitsubishi Heavy Industries, and operated by the Imperial Japanese Navy from 1940 to 1945. Its official design ...

"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), 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 ...

, an expressway in China * G4 (Taichung Metro), also known as Songzhu Station or Jiushe Station, a station under construction in the Taichung Metro * G4-class freighter, a cargo ship design

Biology

* G4 EA H1N1, a strain of influenza * G-quadruplex, a DNA secondary structure

Science and technology

* Group 4 element, a class of elements on the Periodic Table * ATC code G04 ''Urologicals'', a subgroup of the Anatomical Therapeutic Chemical Classification System * G4, a type of bi-pin lamp base (socket), a lamp fitting where the pin spacing is 4mm * LG G4 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) image ...

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

Apple Computer

PowerPC G4 PowerPC G4 is a designation formerly used by Apple and Eyetech to describe a ''fourth generation'' of 32-bit PowerPC microprocessors. Apple has applied this name to various (though closely related) processor models from Freescale, a former part ...

, 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 b ...

, a series of personal computers made by Apple Inc in July 1999 **

PowerBook G4 The PowerBook G4 is a series of notebook computers manufactured, marketed, and sold by Apple Computer between 2001 and 2006 as part of its PowerBook line of notebooks. The PowerBook G4 runs on the RISC-based PowerPC G4 processor, designed by th ...

, a series of Professional notebooks made by Apple Inc in 2001 ** iMac G4, a series of personal computer made by Apple Inc in January 2002 ** Xserve G4, an Xserve server made by Apple Inc in May 2002 ** iBook G4, an

iBook iBook is a line of laptop computers designed, manufactured, and sold by Apple Computer from 1999 to 2006. The line targeted entry-level, consumer and education markets, with lower specifications and prices than the PowerBook, Apple's higher-en ...

series of consumer notebooks in October 2003 ** Mac Mini G4, a Mac Mini series of ultracompact computer in January 2005

Entertainment

* G4 (American TV network), an American television channel * G4 (Canadian TV channel), a former Canadian television channel * G4 (band), a British vocal troupe * Grob's attack, an opening move in chess

Organisations

G4 nations The G4 nations, comprising Brazil, Germany, India, and Japan, are four countries which support each other's bids for permanent seats on the United Nations Security Council. Unlike the G7, where the common denominator is the economy and long ...

, 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 ...