Breadcrumb Home > Thesaurus > M Synonyms of monotreme Find synonyms for: Noun 1. monotreme, egg-laying mammal, prototherian usage: the most primitive mammals comprising the only extant members of the subclass Prototheria WordNet 3.0 Copyright © 2006 by Princeton University. All rights reserved.Definition and meaning of monotreme (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: recherch Analogy of the Day: Today’s Analogy Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language