Breadcrumb Home > Thesaurus > S Synonyms of sigma Find synonyms for: Noun 1. sigma, letter, letter of the alphabet, alphabetic character usage: the 18th letter of the Greek alphabet WordNet 3.0 Copyright © 2006 by Princeton University. All rights reserved.Definition and meaning of sigma (Dictionary) TrendingHere are the facts and trivia that people are buzzing about. Chinese New Year History, Meaning, and Celebrations Current Events This Week: February 2024 Valentine's Day Valentine's Day History Mardi Gras 30 "Charlie and the Chocolate Factory" Quotes ✖ Related Content Daily Word Quiz: raconteur Analogy of the Day: Today’s Analogy Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language