• Oo (digraph), a digraph in orthography
• Oô
  Oô
  Oô is a commune in the Haute-Garonne department in the Midi-Pyrénées region in southwestern France.-Populaiton:Its inhabitants are called Ousiens.-External links:*...
  
  , a commune in France
• OO gauge
  OO gauge
  OO gauge or OO scale model railways are the most popular standard-gauge model railway tracks in the U.K. This track gauge is one of several 4mm-scale standards used, but it is the only one to be served by the major manufacturers...
  
  , a 1:76.2 modelling scale in model railroading
• ‘Ō‘ō, an extinct bird of the genus Moho
• Object-oriented programming
  Object-oriented programming
  Object-oriented programming is a programming paradigm using "objects" – data structures consisting of data fields and methods together with their interactions – to design applications and computer programs. Programming techniques may include features such as data abstraction,...
  
   (OOP), a computer programming paradigm
• OpenOffice
  OpenOffice.org
  OpenOffice.org, commonly known as OOo or OpenOffice, is an open-source application suite whose main components are for word processing, spreadsheets, presentations, graphics, and databases. OpenOffice is available for a number of different computer operating systems, is distributed as free software...
  
  , an open-source application suite
• Official Observer, an appointed amateur radio operator
• Original Oratory
  Original Oratory
  Original Oratory is a competitive event in the National Forensic League, National Catholic Forensic League, and other high school forensic competitions in which competitors deliver an original speech on a subject of their choosing, though the speech must be factual....
  
  , a competitive event in high school forensic competitions
• SkyWest Airlines
  Skywest Airlines
  Skywest Airlines Pty Ltd is a regional airline company based in Perth, Western Australia, Australia; servicing key towns in the state of Western Australia, Darwin, Northern Territory and Melbourne, Victoria; as well as charter flights to Bali, Indonesia....
  
  , IATA code OO
• Belgium
  Belgium
  Belgium , officially the Kingdom of Belgium, is a federal state in Western Europe. It is a founding member of the European Union and hosts the EU's headquarters, and those of several other major international organisations such as NATO.Belgium is also a member of, or affiliated to, many...
  
  , OO (Oscar, Oscar), ICAO aircraft registration prefix
• Oakley, Inc.
  Oakley, Inc.
  Oakley, Inc., based in Foothill Ranch, California, makes sport equipment including sunglasses, sports visors, and ski goggles, as well as watches, clothing, bags, backpacks, shoes, prescription glasses, football and hockey eyewear, Golf gear and other accessories...
  
  , NYSE stock ticker symbol OO
• OO, the Newtwork Rail depot code for the carriage shed at Old Oak Common TMD
  Old Oak Common TMD
  Old Oak Common TMD is situated to the west of London, in Old Oak Common. The Traction Maintenance Depot is the main facility for the storage and servicing of locomotives and multiple-units which utilise Paddington Station. The depot codes are 'OC' for the diesel depot, and 'OO' for the carriage shed...
  
  
• Ozzy Osbourne
  Ozzy Osbourne
  John Michael "Ozzy" Osbourne is an English vocalist, whose musical career has spanned over 40 years. Osbourne rose to prominence as lead singer of the pioneering English heavy metal band Black Sabbath, whose radically different, intentionally dark, harder sound helped spawn the heavy metal...
  
  , a musician
• O.o or o.O, emoticon used in online chat (appears as two eyes) to describe confused or scared

See also

• 00 (disambiguation)
• OOO (disambiguation)
• ∞, a symbol used to indicate infinity
  Infinity
  Infinity is a concept in many fields, most predominantly mathematics and physics, that refers to a quantity without bound or end. People have developed various ideas throughout history about the nature of infinity...
  
  
• ᅇ, an obsolete unit of the Hangul alphabet
• Double-O
  Double-O
  Michael Aguilar, better known by his stage name Double O, is an American producer and one half of the acclaimed hip-hop group Kidz in the Hall.-Early life:...
  
  , a producer and half of hip-hop duo Kidz in the Hall
• Old Order (disambiguation)
  Old Order (disambiguation)
  Old Order commonly refers to Ancien Régime, the French term for the aristocratic, social, and political system established in France under the Valois and Bourbon dynasties .Old order may also refer to:...