[tur-shee-uh m kwid; Latin ter-ti-oo m kwid]
- something related in some way to two things, but distinct from both; something intermediate between two things.
Origin of tertium quid
1715–25; < Latin, translation of Greek tríton·ti some third thing
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
- an unknown or indefinite thing related in some way to two known or definite things, but distinct from boththere is either right or wrong, with no tertium quid
C18: from Late Latin, rendering Greek triton ti some third thing
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
Word Origin and History for tertium quid
1724, Latin, literally "third something," loan-translation of Greek triton ti (Plato), used in alchemy for "unidentified element present in a combination of two known ones."
Online Etymology Dictionary, © 2010 Douglas Harper