What is "o2"

Chromophore \Chro"mo*phore\, n. [Gr. ? color + fe`rein to bear.] (Chem.) Any chemical group or residue (as NO2; N2; or O2) which imparts some decided color to the compound of which it is an ingredient.

sym. (context medicine English) Both eyes.

Österreich 2 (abbreviated to Ö2; previously known as Österreich-Regional, ÖR) is the name given to the regional radio service for Austria and South Tyrol, Italy, aired by the ORF public broadcasting corporation. It consists of nine stations serving the nine federal states respectively. All regional radio stations are also broadcast via satellite at 19.2° east.

Telefónica Ireland was a broadband and telecommunications provider in Ireland that traded under the O2 brand (typeset as O). O2 Ireland was previously called Esat Digifone when it was owned by Esat Telecommunications (and Telenor) from 1997 to 2006.

O2 Ireland became a subsidiary of Telefónica in 2006, after its parent company O2 in the United Kingdom was purchased. In June 2013, Hutchison Whampoa announced it would acquire the Irish arm of O2 for €780m. O2 was merged into Hutchison Whampoa's subsidiary Three Ireland in March 2015.

O is the sixth studio album of the rock band FireHouse. It was released in 2000 and it's the only album to feature the late Bruce Waibel on bass.

O2 is the second studio album by American boyband O-Town, following the success of their triple-platinum self-titled debut album.

Telefónica UK Limited ( trading as O2 – stylised as O) is a telecommunications services provider in the United Kingdom owned by the Spanish multinational Telefónica. It is the second-largest mobile telecommunications provider in the United Kingdom after EE Limited, and is headquartered in Slough.

O2 was formed in 1985 as Cellnet, a 60:40 joint venture between BT Group and Securicor. In 1999, BT Group acquired Securicor's 40 percent share of Cellnet and the company was later rebranded as BT Cellnet. In June 2000 BT Cellnet launched the world’s first commercial General Packet Radio Service. BT Cellnet, together with BT Group's mobile telecommunications businesses in Germany, Ireland and the Netherlands were part of the BT Wireless division. This was spun off from the BT Group in 2002 to form a new holding company, mmO2 plc, which introduced the new "O2" brand for the businesses. mmO2 plc was subsequently renamed O2 plc.

O2 plc was purchased by the Spanish telecommunications company Telefónica in 2006 for £18 billion. Under the terms of the acquisition, Telefónica agreed to retain the "O2" brand and the company's UK headquarters. O2 plc became Telefónica Europe.

O is Gospel singer Tonéx's second major release. It was released under Zomba Records in 2002 and spawned two major hits, "God Has Not 4Got" and "Bout A Thang", which had a video for the single. The album reached number seven on the Billboard Top Gospel Albums chart, number twenty on the Top Contemporary Christian chart, number twenty on the Top Heatseekers chart, and number 66 on the R&B Albums Chart.