Σ

Unicode name GREEK CAPITAL LETTER SIGMA U+03A3
See also: [U+2211 N-ARY SUMMATION], Ʃ [U+01A9 LATIN CAPITAL LETTER ESH], and [U+2D49 TIFINAGH LETTER YI]

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 (S) (uppercase, lowercase σ)

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