SO

SO or so may refer to:

Arts and entertainment

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

SO (complexity), second-order logic in descriptive complexity
Special orthogonal group, a subset of an orthogonal group
- 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

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

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