O3 may refer to: *O₃, the molecular formula for

ozone Ozone (), or trioxygen, is an inorganic molecule with the chemical formula . It is a pale blue gas with a distinctively pungent smell. It is an allotrope of oxygen that is much less stable than the diatomic allotrope , breaking down in the lo ...

*, the ozonide anion *''O₃'', the 1993 debut album by the techno band

Sunscreem Sunscreem are a techno/house music band from Essex, England that scored a number of hits on the US Hot Dance Music/Club Play chart throughout the 1990s and into the 21st century. Sunscreem also has the rare reputation as a techno-based band t ...

*''

O3 A Trilogy Dominici was a progressive metal band formed in 2005 by former Dream Theater vocalist Charlie Dominici. History The band's only released work to date is the ''O3 Trilogy'', a series of three concept albums about the story of a terrorist sleepe ...

'', a 2008 concept album trilogy by progressive metal band Dominici *O3 star, in stellar classification, a subclass of type O stars * O-3, the pay grade for the following officer ranks in the U.S. uniformed services: **

Captain Captain is a title, an appellative for the commanding officer of a military unit; the supreme leader of a navy ship, merchant ship, aeroplane, spacecraft, or other vessel; or the commander of a port, fire or police department, election precinct, e ...

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

Lieutenant A lieutenant ( , ; abbreviated Lt., Lt, LT, Lieut and similar) is a commissioned officer rank in the armed forces of many nations. The meaning of lieutenant differs in different militaries (see comparative military ranks), but it is often sub ...

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

Haplogroup O3 (Y-DNA) Haplogroup O-M122 (also known as Haplogroup O2 (formerly Haplogroup O3)) is an Eastern Eurasian Y-chromosome haplogroup. The lineage ranges across Southeast Asia and East Asia, where it dominates the paternal lineages with extremely high frequ ...

, a Y-DNA Haplogroup *

Oldershaw O-3 The Oldershaw O-3 is an American high-wing, single seat, V-tailed glider that was designed by Vernon Oldershaw. Two examples were constructed as gliders and then both were later converted to motor gliders.Said, Bob: ''1983 Sailplane Directory, ...

, glider * USS ''O-3'' (SS-64), a 1917 United States O class submarine *

Otoyol 3 Otoyol 3 ( en, Motorway 3), also known as the European Motorway ( tr, Avrupa Otoyolu) and abbreviated as the O-3 is a long otoyol in East Thrace, Turkey. The O-3 runs from Edirne to Istanbul and is the only motorway in Turkey located entirely i ...

, a Turkish motorway from Edirne to Istanbul *Oskarshamn 3, unit 3 at

Oskarshamn Nuclear Power Plant The Nuclear power station Oskarshamn is one of three active nuclear power stations in Sweden. The plant is about north of Oskarshamn, directly at the Kalmarsund at the Baltic Sea coast and with one active reactor, producing about 10% of the el ...

in Sweden * ''O3'' (album), a 2008 album by Son of Dave * LNER Class O3, a class of British steam locomotives

See also