On
On, on, or ON may refer to:

Arts and entertainment
Music
On (band), a solo project of Ken Andrews
On (EP), a 1993 EP by Aphex Twin
On (Echobelly album), 1995
On (Gary Glitter album), 2001
On (Imperial Teen album), 2002
On (Elisa album), 2006
On (Jean album), 2006
On (Boom Boom Satellites album), 2006
On (Tau album), 2017
"On" (song), a 2020 song by BTS
"On", a song by Bloc Party from the 2006 album A Weekend in the City

Other media
Ön, a 1966 Swedish film
On (Japanese prosody), the counting of sound units in Japanese poetry
On (novel), by Adam Roberts
ONdigital, a failed British digital television service, later called ITV Digital
Overmyer Network, a former US television network

Places
On (Ancient Egypt), a Hebrew form of the ancient Egyptian name of Heliopolis
On, Wallonia, a district of the municipality of Marche-en-Famenne
Ahn, Luxembourg, known in Luxembourgish as On
Ontario, a Canadian province

Science, technology, and mathematics
Biology and medicine
Operative note, documentation of care relating to an operation
Optic neuritis, especially relevant in multiple sclerosis
Osteonecrosis, death of bone tissue
Osteonectin, a glycoprotein

Other uses in science, technology, and mathematics
ON Semiconductor, a semiconductor manufacturing company
O'Nan group, a mathematical group
OS/Net, the OpenSolaris Community
On, the proper class of all ordinal numbers

Other uses
On (biblical figure), son of Peleth
On (company), a Swiss athletic shoe and sportswear company
On Kawara, Japanese artist
Nauru Airlines (IATA airline designator ON)Ollio

Old Norse, a North Germanic language commonly referenced in etymology
Ontology, a branch of philosophy that deals with the concept of being
On'yomi, reading of Japanese kanji characters
Order of the Nation, a Jamaican honour
Overground Network, a railway scheme in South London
ON convoys, a series of WWII trade convoys
Orka náttúrunnar (ON Power), Icelandic geothermal power company
On, a Basque-language honorific equivalent to Spanish Don (honorific)

See also
Yōon