existential

Abstract is a related term of existential.

As a noun abstract

is abstract.

As an adjective existential is

of, or relating to existence.

Ultimate is a related term of existential.

As adjectives the difference between ultimate and existential

is that ultimate is final; last in a series while existential is of, or relating to existence.

As a noun ultimate

is the most basic or fundamental of a set of things.

Cosmological is a related term of existential.

As adjectives the difference between cosmological and existential

is that cosmological is of or pertaining to cosmology, or to the overall structure of the universe while existential is of, or relating to existence.

As adjectives the difference between ontological and existential

is that ontological is of, or relating to, ontology while existential is of, or relating to existence.

As a noun taxonomy

is the science or the technique used to make a classification.

As an adjective existential is

of, or relating to existence.

As adjectives the difference between existential and psychological

is that existential is of, or relating to existence while psychological is of or pertaining to psychology.

As adjectives the difference between existential and nonexistential

is that existential is of, or relating to existence while nonexistential is not existential.