sigma

     

Sigma (upper case Σ, lower case σ, lower case in wor-final position ς) is the eighteenth letter of the Greek alphabet. In the system of Greek numerals it has a value of 200. When used at the end of a word, and the word is not all upper case, the final form (ς) is used. (e.g. Ὀδυσσεύς (Odysseus) - Note the two sigmas in the center of the name, and the word-final sigma at the end.) Not to be confused with the cedilla ç.