NOUMENON

noumenon, thing-in-itself

(noun) the intellectual conception of a thing as it is in itself, not as it is known through perception

Source: WordNet® 3.1

Etymology

Noun

noumenon (plural noumena)

(from Kantian philosophy on) A thing as it is independent of any conceptualization or perception by the human mind, postulated by practical reason but existing in a condition which is in principle unknowable and unexperienceable.

Synonym: thing-in-itself

Antonym: phenomenon

Source: Wiktionary

Nou"me*non, n. Etym: [NL. fr. Gr. (Metaph.)

Definition: The of itself unknown and unknowable rational object, or thing in itself, which is distinguished from the Ant: phenomenon through which it is apprehended by the senses, and by which it is interpreted and understood; -- so used in the philosophy of Kant and his followers.

Source: Webster’s Unabridged Dictionary 1913 Edition