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
- S.O. (rapper)
Songs
- "So" (Static-X song), 2004 single
- "Sō (New Love New World)", 2008 single by Masaharu Fukuyama
- "So", by War from Why Can't We Be Friends? (1975)
- "So", by Fates Warning from Disconnected (2000)
Other
- "SO" (Sons of Anarchy), the third season premiere of the FX television series Sons of Anarchy
- So Television, a British TV production company
Transportation
- Southern State Parkway, a highway in New York, United States
- Railway line prefix SO of Sotetsu lines
- Austrian Air Services (former IATA airline designator SO)
- Sosoliso Airlines (former IATA airline designator SO)
- Southern Airways (former IATA airline designator 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
Science, technology, and mathematics
Biology and medicine
- Syndromic obesity, excess body fat occurring as part of a syndrome
- Sphincter of Oddi, a muscular valve of the duodenum
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
- Small-outline integrated circuit
- StackOverflow, a programming Q&A site
- Sony's mobile phones in Japan
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(8), a term used in mathematics, the special orthogonal group acting on eight-dimensional Euclidean space
-
s
o
(
n
)
{\displaystyle {\mathfrak {so}}(n)}
, the corresponding special orthogonal Lie algebra
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
Energy industry
- Southern Company (stock symbol SO), a gas and electric utility holding company based in the Southern United States
- Esso, a trading name for ExxonMobil, short for Standard Oil
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)
- So (Hebrew: סוֹא), King of Egypt, usually identified with Osorkon IV
Food
- So (dairy product), a type of dairy product made in ancient Japan
- Shell on, a form of presentation in shrimp marketing
Other uses
- 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
- Strikeout, in baseball
- Significant other, a partner in an intimate relationship