tertium quidter·ti·um quid
something of uncertain or unclassifiable nature, related to, but distinct from, two, usually opposite, things
Origin of tertium quidL, literally , third something
- Something that cannot be classified into either of two groups considered exhaustive; an intermediate thing or factor.
- A third person or thing of indeterminate character.
Origin of tertium quidLate Latin : Latin tertium, from neuter of tertius, third + quid, something.