Oh
Oh, OH, or Oh! is an interjection, often proclaiming surprise.  It may refer to:

Arts and entertainment
Music
Albums
Oh! (Girls' Generation album), 2010
Oh! (ScoLoHoFo album), 2003
OH (ohio), by Lambchop, 2008
Oh!, an EP that came with the preorders of Oh! Gravity. by Switchfoot, 2006

Songs
"O (Oh!)", 1920 by Ted Lewis, 1953 by Pee Wee Hunt
"Oh" (Ciara song), 2005
"Oh!" (Girls' Generation song), 2010
"Oh!" (Pink Lady song), 1981
"Oh" (Stray Kids song), 2021
"Oh!", by Boys Noize from Oi Oi Oi
"Oh!", by The Breeders from Pod
"Oh", by Dave Matthews from Some Devil
"Oh", by Fugazi from The Argument
"Oh", by Juliana Hatfield from Made in China
"Oh!", by Micky Green from White T-Shirt
"Oh!", by Sleater-Kinney from One Beat
"Oh", by Spratleys Japs from Pony
"Oh!", by The Trudy
"Oh," by Underworld, recorded for the soundtrack to A Life Less Ordinary, 1997

Other media
Oh! (TV channel), an Australian cable TV channel owned by Optus Television
Oxygen, an American TV channel formerly called "Oh!"
Oh, a Boov alien from Home (2015)

People
Oh (surname), Korean surname romanized as "Oh" or "O"
Oh (Japanese surname), Japanese surname derived from Wang(王)
Ou (surname), Chinese and Cantonese surnames pronounced as "Oh" or "O"
Dennis Oh, Korean actor
Nadia Oh, English vocalist

Science and technology
Chemistry
OH, the hydroxy functional group
OH−, hydroxide anion
•OH, hydroxyl radical
OH, the alcohol class of compounds, that possess a hydroxy functional group

Other uses in science and technology
OH, prefix of hominid fossils found at Olduvai Gorge
OH, designation in the Unified Soil Classification System for organic-rich clay or silt of high plasticity
Oh, the point group of octahedral molecular geometry
Ohnesorge number, a dimensionless number that relates the viscous forces to inertial and surface tension forces
Oral hygiene

Transportation
OH, registration prefix for aircraft registered in Finland
Comair (IATA airline code OH)
PSA Airlines (IATA airline code OH)
Observation helicopter, in military abbreviation

Other uses
Ohio, US (postal abbreviation)
O.H., post-nominal letters for the Brothers Hospitallers of Saint John of God