ex·is·ten·tial 
(ĕg′zĭ-stĕnshəl, ĕk′sĭ-)
(ĕg′zĭ-stĕnshəl, ĕk′sĭ-)adj.
1. Of, relating to, or dealing with existence.
2. Based on experience; empirical.
3. Of or as conceived by existentialism or existentialists: an existential moment of choice.
4. Linguistics Of or relating to a construction or part of a construction that indicates existence, as the words there is in the sentence There is a cat on the mat.
n.
Linguistics
Linguistics
An existential word or construction.
ex′is·tential·ly adv.