SO

So, a common English conjunction and adverb, indicative of comparative degree.

SO or S-o is a common acronym used to indicate Significant other.

SO (and variations) may refer to:
* So (kana), the romanisation of the Japanese kana そ and ソ
* Somalia, ISO 3166-1 alpha-2 country code
* Somali language, (ISO 639)
** .so, the top-level Internet domain of Somalia
* Special Olympics, an international organization created to help people with intellectual disabilities develop self-confidence and social skills through sports training and competition
* Sao civilisation or So, an African civilisation that flourished from ca. the 6th century to ca. 15th century

In business:
* Sales order, an order received by a business from a customer
* Sosoliso Airlines, IATA airline designator
* Superior Aviation, IATA airline designator
* Southern Airways, former IATA airline designator
* Southern Company, stock ticker symbol
* Standard Oil (1870-1911), a predominant integrated oil producing, transporting, refining, and marketing company; dissolved by the US Supreme Court

In entertainment:
* Sierra Oscar, the call sign used by police officers in ITV serial drama The Bill
* Star Ocean, a role-playing game series by Enix

In music:
* "So" (album), a music album by Peter Gabriel
* So (band), a duo from the 80s formed by two members of The Opposition
* Symphony orchestra, a type of orchestra
* So the 5th note of the Solfege

In military and police:
* SO10, former Specialist Operations designation for the Metropolitan Police's Crime Operations Group
* SO11 or Specialist Operations - Intelligence, a defunct branch of Scotland Yard
* SO19 The Specialist Firearms Command of Scotland Yard, now known as CO19
* Special ops, another name for special forces

In people:
* So (surname), a Chinese surname

In places:
* Canton of Solothurn, Switzerland

In science and technology:
* SO, SO alias for SOIC chip "package"
* .so, a filename extension for "shared object" dynamic library files in Unix
* Science Olympiad, a primarily American elementary, middle school, or high school team competition that requires knowledge of various science topics and engineering ability
* Service cable/cord, Oil-resistant, a type of power cord
* Shift Out, an ASCII control character in computing
* SO(4), in mathematics, the group of rotations about a fixed point in four-dimensional Euclidean space
* SO(5), in mathematics, the special orthogonal group of degree 5 over the field R of real numbers
* SO(8), in mathematics, the special orthogonal group acting on eight-dimensional Euclidean space
* SO(10) (physics), in particle physics, one of the grand unified theories (GUT) is based on the SO(10) Lie group
* Special orthogonal group, a subset of an orthogonal group
* StarOffice, a commercial package of office software produced by Sun Microsystems
* Sulfur monoxide, a compound with the chemical formula SO

In other:
* SO, Sony or Sony Ericsson's mobile phones of NTT DoCoMo in Japan

See also

* Esso, an international trade name used by the Exxon Mobil Corporation and its related companies
* So and so, disambiguation page