Breadcrumb Home > Thesaurus > F Synonyms of fos Find synonyms for: Noun 1. field-grade officer, field officer, FO, commissioned military officer usage: an officer holding the rank of major or lieutenant colonel or colonel WordNet 3.0 Copyright © 2006 by Princeton University. All rights reserved.Definition and meaning of fos (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: quisling Analogy of the Day: Today’s Analogy Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language