/ Thesaurus / H Synonyms of hylobates syndactylus Find synonyms for: Noun1. siamang, Hylobates syndactylus, Symphalangus syndactylus, lesser apeusage: large black gibbon of Sumatra having the 2nd and 3rd toes partially united by a webWordNet 3.0 Copyright © 2006 by Princeton University. All rights reserved. Related Content Daily Word Quiz: tenacious Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language