Sigma (/ ˈsɪɡmə / SIG-mə; uppercase Σ, lowercase σ, lowercase in word-final position ς; Greek: σίγμα) is the eighteenth letter of the Greek alphabet.

Sigma (uppercase/lowercase Σ σ ς) is the 18th letter of the Greek alphabet. It is used to represent the "s" sound in Ancient and Modern Greek. In the system of Greek numerals, it has a value of 200. Letters that came from it include the Roman S and Cyrillic С.

Sigma (uppercase Σ, lowercase σ or in word-final position ς; Greek: σίγμα) is the 18th letter of the Greek alphabet. In the Greek numeral system, the Sigma symbol denotes the value of 200. Sigma is the only one of the 24 Greek alphabet letters that has two different lowercase symbols.

Sigma (Σ, σ) is the eighteenth letter of the Greek alphabet, commonly used in both ancient and modern Greek. It represents the “s” sound in lowercase and “S” in uppercase.

Sigma is a significant letter in the Greek alphabet and is denoted by the symbols uppercase (Σ) and lowercase (σ or ς). It is the 18th letter and is primarily used in mathematics, science, and engineering. The lowercase sigma (ς) is used at the end of a word, while σ is used in other positions.