OD or Od may refer to:

Education

* Old Diocesan, a former pupil of Diocesan College * Old Dunelmian, a former pupil of Durham School

Medicine

* OD or o.d., an List of abbreviations used in medical prescriptions, abbreviation used in medical prescriptions for or "once daily" both meaning "take once every day" * Doctor of Optometry (O.D.) * , , or , meaning "right eye" in general ophthalmologic or optometric usage, particularly in Eyeglass prescription, eyeglass prescriptions * Osteochondritis dissecans, a medical disease affecting the joints of both humans and animals * Overdose, the use of a drug in quantities greater than recommended

Music

* Oblivion Dust, a Japanese rock band * One Direction, a British/Irish pop music band * Orphei Drängar, a Swedish male choir * O.D, a song by Sunna from the album ''One Minute Science'' (2000) * ''Overly Dedicated'', a 2010 mixtape by Kendrick Lamar * ''The OD EP'', a 2012 extended play by Danny Brown (rapper), Danny Brown

Organizations

* Batik Air Malaysia (IATA airline code OD) * ''Jewish Ghetto Police, Ordnungsdienst'' , a collaborationist organization in Nazi-occupied Poland * Organization development

People and characters

* O.D. (musician), a member of Velcra * Super OD, a Ghanaian actor * O.D (Gatchaman Crowds), O.D (''Gatchaman Crowds''), a character in the anime series ''Gatchaman Crowds'' * Ód or Óðr, a Nordic god

Places

* Odisha, India * Stormarn (district), Germany (vehicle plate code OD)

Science and technology

* Optical density * Outside diameter (also: ''O.D.''), cylinder or pipe external diameter * Ordnance datum, in Britain, an Ordnance Survey data point * od (Unix), a Unix program * Object Desktop, a suite of skinning and customization programs by Stardock, or ''ObjectDock'', another program by the same company * Optical disc * Organization development, the study of organizational change and performance * Ordinal definable set, a set requiring only finitely-many ordinals to define under first-order logic.

Other uses

* Od language, an Indo-Aryan language of Pakistan * Odic force or Od, a life force * ''Occupation Double'', a Quebec reality show that started in 2003 * Official Declaration, part of Latter-day Saint scripture * Olive drab, a color, particularly of some United States Army uniforms * Online dating * Original dance, the second part of an ice dancing competition * Order of Distinction, a civil honour of Jamaica * OD - original designation in Taxonomy (biology), Taxonomy