Plethodontidae plet·ho·don·tidae uncommon noun 1. small mostly terrestrial New World salamanders having neither lungs nor gills as adults Synonymsfamily Plethodontidae Related words Broader terms amphibian family Parts Urodella Part of Plethodonlungless salamanderDesmograthusAneidesBatrachosepsHydromantes WordNet 2.1 (Princeton University). WordNet 2.1 Copyright Princeton University. All rights reserved.