It requires greater skill than ours to interfere between man and wife, even without the tertium quid of an astounding baby.
Now what is this tertium quid that is to be the medium of all synthetical judgements?
The brute threw up her head and went down with a scream, the tertium quid upon her, and the nervous grin still set on his face.
This means something which is neither a variety nor yet a species—a tertium quid.
Existence or reality therefore must be a tertium quid, apart from motion and rest, not the sum total of those two items.
What're you going to do about that tertium quid you've annexed?
The word 'crank,' which became familiar at the time of Guiteau's trial, fulfilled the need of a tertium quid.
Is Good identical with pleasure, or with intelligence, or is it a tertium quid, distinct from both?
“tertium quid,” said Lady Poynting Mallow, with a luminous incorrectness.
tertium quid alone makes any pretence at impartiality, and his is the result of indifference, not of justice.
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."