Sigma
Sigma 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 (when the word is not all caps), 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.
The name of sigma, according to one hypothesis, may continue that of Phoenician Samekh. According to a different theory, its original name may have been san (the name today associated with another, obsolete letter), while sigma was a Greek innovation that simply meant "hissing", based on a nominalization of a verb σί
© Symbols.com