SO
SO or so may refer to:

Arts and entertainment
Music
So (album), an album by Peter Gabriel
So (band), a duo from the 1980s formed by two members of The Opposition
"So" (Static-X song), a song by Static-X
"Sō (New Love New World)", a song by Masaharu Fukuyama
"So", a song by War from Why Can't We Be Friends?
"So", a song by Fates Warning from Disconnected
S.O. (rapper)

Other
"SO" (Sons of Anarchy), the third season premiere of the FX television series Sons of Anarchy
So Television, a British TV production company

Relationships
Significant other, a partner in an intimate relationship

Businesses
Austrian Air Services (former IATA airline designator SO)
Sosoliso Airlines (former IATA airline designator SO)
Southern Airways (former IATA airline designator SO)
Southern Company (stock symbol SO)
Superior Aviation (IATA airline designator SO)

Language
So language (Democratic Republic of Congo), a Bantu language
Sô language, a Katuic language (Mon-Khmer) of Laos and Thailand
Swo language, a Bantu language of Cameroon
Soo language, a Kuliak language of Uganda
Somali language (ISO 639 language code "so")
So (kana), a Japanese kana
So (word), an English word

Places
So, Iran, a village in Isfahan Province, Iran
Canton of Solothurn, Switzerland
So Phisai District, Bueng Kan Province, Thailand
SO postcode area, UK, the Southampton postcode area
Somalia (ISO 3166-1 alpha-2 country code SO)
South Otago, part of New Zealand's South Island
Southern State Parkway, a highway in New York, United States

Science, technology, and mathematics
Computing
.so, the top-level Internet domain of Somalia
.so, a filename extension for a shared object (a dynamic library or module) in Unix and Linux
Shift Out, an ASCII control character in computing
Small-outline integrated circuit
StackOverflow, a programming Q&A site

Mathematics
SO (complexity), second-order logic in descriptive complexity
Special orthogonal group, a subset of an orthogonal group
SO(2), a term used in mathematics, the group of rotations about a fixed point in the Euclidean plane
SO(3), a term used in mathematics, the group of rotations about a fixed point in three-dimensional Euclidean space
SO(4), a term used in mathematics, the group of rotations about a fixed point in four-dimensional Euclidean space
SO(5), a term used in mathematics, the special orthogonal group of degree 5 over the field R of real numbers
SO(8), a term used in mathematics, the special orthogonal group acting on eight-dimensional Euclidean space

Physics and chemistry
Sulfur monoxide
SO(10) (physics), a term used in particle physics, one of the grand unified theories is based on the SO(10) Lie group

Names
Sō, a Japanese surname and given name
Su (surname) (苏/蘇), a Chinese surname and a Korean surname (소) derived from it
So (Korean name) (蘇 or 邵)

Other uses
So (סוֹא), King of Egypt, usually identified with Osorkon IV
So (dairy product), a type of dairy product made in ancient Japan
Sales order, an order received by a business from a customer
Sao civilisation or So, an African civilisation and population that flourished from ca. the 6th century to ca. 15th century
Shell on, a form of presentation in shrimp marketing
Significant other, a partner in a romantic relationship
Strikeout, in baseball

See also
Esso, an Exxon trade name, phonetic version of SO
So and so (disambiguation)
Só (disambiguation)
S0 (disambiguation)