# Σ

Unicode name GREEK CAPITAL LETTER SIGMA U+03A3

## Translingual

### Symbol

Σ

1. (mathematics) Σ. Sum over a set of like terms:
$\sum_{n=1}^2 n^2 = 1 + 4 = 5$

#### Usage notes

(mathematics): Though there exists a distinct symbol () for the purpose of the mathematical summation, the upper case sigma here is often used for convenience.

## Greek

### Letter

Σ (uppercase, lowercase σ)

1. The upper case letter sigma (σίγμα), the 18th letter of the modern Greek alphabet.