O2, O-2, o2, O₂, O², O²⁻ or O²⁺ may refer to:

Science and technology

* or

dioxygen There are several known allotropes of oxygen. The most familiar is molecular oxygen (O2), present at significant levels in Earth's atmosphere and also known as dioxygen or triplet oxygen. Another is the highly reactive ozone (O3). Others are: * ...

, the common allotrope of the chemical element oxygen * , the ion oxide * , the ion

superoxide In chemistry, a superoxide is a compound that contains the superoxide ion, which has the chemical formula . The systematic name of the anion is dioxide(1−). The reactive oxygen ion superoxide is particularly important as the product of t ...

* , the ion dioxygenyl * ,

doubly ionized oxygen In astronomy and atomic physics, doubly ionized oxygen is the ion O2+ (O III in spectroscopic notation). Its emission forbidden lines in the visible spectrum fall primarily at the wavelength 500.7 nm, and secondarily at 495.9 nm. Befor ...

* O2, an EEG electrode site according to the 10–20 system *

SGI O2 The O2 was an entry-level Unix workstation introduced in 1996 by Silicon Graphics, Inc. (SGI) to replace their earlier Indy series. Like the Indy, the O2 used a single MIPS microprocessor and was intended to be used mainly for multimedia. It ...

, a Unix workstation computer *

UOC O2 The Open University of Catalonia ( ca, Universitat Oberta de Catalunya, UOC; ) is a private open university based in Barcelona, Spain. The UOC offers graduate and postgraduate programs in Catalan, Spanish and English in fields such as Psycholo ...

, institutional repository of the Open University of Catalonia * O2, the earliest defined spectral class for stars

Places

The O2 The O2 is a large entertainment district on the Greenwich peninsula in South East London, England, including an indoor arena, a music club, a Cineworld cinema, an exhibition space, piazzas, bars, and restaurants. It was built largely withi ...

, an entertainment district in London, England **

The O2 Arena The O2 Arena, commonly known as the O2 (stylised as The O2 arena), is a multi-purpose indoor arena in the centre of the O2 entertainment complex on the Greenwich Peninsula in southeast London. It opened in its present form in 2007. It has the s ...

, the arena within The O2 *

O2 Arena (Prague) O2 Arena (formerly Sazka Arena, stylised as O2 arena) is a multi-purpose arena, in Prague, Czech Republic. It is home to HC Sparta Prague of the Czech Extraliga and is the second-largest ice hockey arena in Europe. It has hosted important ...

or Sazka Arena, an arena in Prague, Czech Republic *

O2 Centre The O2 Centre is an indoor shopping and entertainment centre that is open for around 18 hours per day located on Finchley Road in North West London, near Hampstead. It is now owned by Landsec, previously X Leisure, and opened in 1998. Despit ...

, an indoor shopping and entertainment centre on Finchley Road, London, England * O2 Residence, a part of the Jumeirah Lake Towers in Dubai, United Arab Emirates *

O2 World (Berlin) '' This article is about the German stadium. You may be looking for the American stadium.'' The Mercedes-Benz Arena ()

, an indoor arena in Berlin, Germany *

O2 World (Hamburg) The Barclays Arena (originally known as the Color Line Arena and formerly known as barclaycard arena and O2 World Hamburg) is a multipurpose arena in Hamburg, Germany. It opened in 2002 and can hold up to 16,000 people (13,800 or 12,947 for spo ...

, an indoor arena in Hamburg, Germany *

Otoyol 2 Otoyol 2 ( en, Motorway 2), abbreviated as , locally referred to as 2. ÇevreyoluUsually colloquially called TEM yolu or TEM in Turkish—which refers to Trans-European Motorway. ( en, The Second Beltway), is a motorway in Istanbul, Turkey that ...

, a motorway in Turkey called "O2" *

The O2 (Dublin) The 3Arena (originally The O2) is an indoor amphitheatre located at North Wall Quay in the Dublin Docklands in Dublin, Ireland. The venue opened as The O2 on 16 December 2008. It was built on the site of the former Point Theatre, a smaller music ...

, the former name of 3Arena *

Ring 2 (Aarhus) Ring 2, or ''Ringvejen'', is the outermost ring road surrounding the city of Aarhus in Denmark. Geography Ring 2 bounds the outer neighborhoods of the central urban area. It is part of the Danish national road network and is numbered O2, the ...

, a road in Aarhus, Denmark, which appears as "O2" on signs * Ring 2 (Copenhagen), a road in Copenhagen, Denmark, which appears as "O2" on signs

Arts, entertainment, and media

Film

* ''O2'' (film), an American-French survival thriller film in production * ''O2'' (2020 film), an Estonian-Latvia-Lithuanian-Finnish historical spy thriller film * ''O2'' (2022 film), an Indian Tamil language survival thriller film

Music

Albums

* ''O₂'' (FireHouse album) (2000) album of the rock band FireHouse * ''O2'' (O-Town album) (2002) album by American boy band O-Town * O₂ (Tonéx album) (2002) album by Gospel singer Tonéx * '' O2: Avalon Remixed'', a 2002 album by Avalon * ''O2'' (Son of Dave album), 2006 album by Son of Dave

Songs

* "O2", a song by Orange Range from ''

Panic Fancy ''Panic Fancy'' (stylized in all caps) is Japanese alternative rock (a.k.a. mixture rock) band Orange Range's ninth major album. Upon its launch on July 9, 2008, ''Panic Fancy'' topped the Japanese Oricon Album Charts at #1 position. The album fea ...

'' * "O2", a 2002 song by Sleater-Kinney from ''

One Beat ''One Beat'' is the sixth studio album by the American rock band Sleater-Kinney, released on August 20, 2002, by Kill Rock Stars. It was produced by John Goodmanson and recorded between March and April 2002 at Jackpot! Studio in Portland, Orego ...

'' * "O2", a song by Suho from '' Self-Portrait''

Other arts, entertainment, and media

* Ö2, a radio service for Austria and South Tyrol * O2, a character in '' Kirby 64: The Crystal Shards''

Businesses and organisations

* O₂, trading name for

Telefónica Europe O2 (typeset as O2) is a global brand name owned by the Spanish telecommunications company Telefónica. The company uses the O2 brand for its subsidiaries in the United Kingdom and Germany. Since 2018, it is also used as an online-only flanker br ...

, a European telecommunications provider **

O2 Store The O2 Store is a chain of retail stores operated by Telefónica Europe, specializing in mobile phones. As of January 2014, O2 has opened over 450 stores in the United Kingdom. O2 Stores come in 2 formats - Franchise and Retail. The latter are owne ...

, a chain of retail stores owned and operated by Telefónica Europe, with regional subsidiaries: **

O2 (brand) O2 (typeset as O2) is a global brand name owned by the Spanish telecommunications company Telefónica. The company uses the O2 brand for its subsidiaries in the United Kingdom and Germany. Since 2018, it is also used as an online-only flanker br ...

, Telefónica mobile network global brand name **

O2 (Ireland) Telefónica Ireland was a broadband and telecommunications provider in Ireland that traded under the O2 brand (typeset as O2). O2 Ireland was previously called Esat Digifone when it was owned by Esat Telecommunications (and Telenor) from 1997 ...

, merged into Three Ireland **

O2 (UK) O₂ UK (legally incorporated as Telefonica UK Limited, stylized as O₂) is a British telecommunications services provider, headquartered in Slough, England. It operates under the O2 brand. It is owned by Virgin Media O2, a 50:50 joint ventu ...

O2 Czech Republic O2 Czech Republic (operating under the O2 brand) is a major integrated operator in the Czech Republic. It is now operating more than six million lines, both fixed and mobile, making it one of the Czech Republic’s leading providers of fully co ...

Telefónica Germany Telefónica Germany GmbH & Co. OHG (; also called Telefónica Deutschland ) is a provider of broadband, landline and mobile telecommunications in Germany. The company trades as O2 (typeset as O2). The company was renamed from Telefónica O ...

** Telefónica Slovakia * O2 Academy, a chain of music venues *

O2 Wireless USA h2o Wireless is a United States-based prepaid GSM phone and mobile Internet service, utilizing the AT&T GSM 4G LTE network. It is a brand of mobile virtual network operator (MVNO) Locus Telecommunications, a subsidiary of Telrite Holdings, I ...

or H2O Wireless, a prepaid wireless service by Locus Telecommunications *

O2TV O2TV (stylized as O!2) is a Russian independent TV channel, the target audience of which are young people between 16 and 35, who, as the 2006 presentation reads, would constitute an influential portion of the electorate in the Russian legislative ...

, a Russian independent socially political TV channel

Vehicles and vessels

Cessna O-2 Skymaster The Cessna O-2 Skymaster (nicknamed "Oscar Deuce") is a military version of the Cessna 337 Super Skymaster, used for forward air control (FAC) and psychological operations (PSYOPS) by the US military between 1967 and 2010. Design and develo ...

, a military twin-engine light aircraft *

Douglas O-2 The Douglas O-2 was a 1920s American observation aircraft built by the Douglas Aircraft Company. Development The important family of Douglas observation aircraft sprang from two XO-2 prototypes, the first of which was powered by the 420 hp ...

, a military single-engine observation biplane * ''O 2''-class submarine, a class of submarines of the Royal Netherlands Navy * Oldershaw O-2, a glider * SP&S Class O-2, a 1910 steam locomotives class * USS ''O-2'' (SS-63), a 1918 United States O class submarine *

Orbital O2 The Orbital O2 is a floating 2MW tidal stream generator, tidal turbine that began generating power for the UK grid in July 2021. It was designed and built by Orbital Marine Power Ltd., a privately held company with offices in Orkney and Edinburgh. ...

, a tidal power turbine in Orkney *

GNR Class O2 The Great Northern Railway (GNR) Class O2 was a class of three-cylinder 2-8-0 steam locomotives designed by Nigel Gresley for freight work and built by the GNR from 1921. Further examples were built by the London and North Eastern Railway (LNER ...

, a class of British steam locomotives classified O2 by both the GNR and the LNER

Other uses

* O-2, a pay grade in the US uniformed services **

First lieutenant (United States) First lieutenant is a commissioned officer military rank in many armed forces; in some forces, it is an appointment. The rank of lieutenant has different meanings in different military formations, but in most forces it is sub-divided into a se ...

in the Army, Marine Corps, Air Force, and Space Force **

Lieutenant (junior grade) Lieutenant junior grade is a junior commissioned officer rank used in a number of navies. United States Lieutenant (junior grade), commonly abbreviated as LTJG or, historically, Lt. (j.g.) (as well as variants of both abbreviations), ...

in the Navy, Coast Guard, Public Health Service Commissioned Corps, and NOAA Commissioned Officer Corps