/ Dictionary / Index T tertium quid: Meaning and Definition of Find definitions for: ter•ti•um quid Pronunciation: (tûr'shē-um kwid' Lat. ter'ti-&oobrevem&sec kwid'), [key] something related in some way to two things, but distinct from both; something intermediate between two things. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. tertiary syphilis Tertullian Related Content Daily Word Quiz: spectral Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language