Oh is an interjection with many uses, often said by people realizing something. Ex. Oh, now I see.It may also refer to:
Companies
Oh! Production, an anime studio in Japan
Television
Oh Yeah! Cartoons, a Nickelodeon show.
Oh!, a defunct Australian subscription television channel.
Oh! Oxygen, a television network
Magazine
Oh! Only Health, a health magazine
Abbreviations
A pronounced abbreviation for the number Zero
OH, an abbreviation for the U.S. State of Ohio (United States postal abbreviations)
Comair (IATA airline designator)
in chemistry:
Hydroxy
Hydroxide
Specifically, the Hydroxyl radical
The functional alcohol group in a molecule ie: CH3CH2OH
is a USCS symbol for an organic-rich clay and/or silt of high plasticity
Olduvai Hominid
A former employee of the Appalachian Mountain Club's Hut System in the White Mountains of New Hampshire (Old Hutmans Association)
Old Harrovian, a former pupil at Harrow School, England
Old Herefordian, a former pupil of Here
Source:
http://en.wikipedia.org/wiki/Oh