|Unicode name||GREEK CAPITAL LETTER SIGMA|
|Unicode block||Greek and Coptic|
- (mathematics) Σ. Sum over a set of like terms:
- (topology) suspension or reduced suspension
- (mathematics) A class (in the arithmetical hierarchy) of formulae whose outermost unbounded quantifiers are existential quantifiers
(mathematics): Though there exists a distinct symbol (∑) for the purpose of the mathematical summation, the upper case sigma here is often used for convenience.