Noun \Noun\, n. [OF. noun, nun, num, non, nom, F. nom, fr. L. nomen name. See Name.]

(Gram.) A word used as the designation or appellation of a creature or thing, existing in fact or in thought; a substantive.

Note: By some grammarians the term noun is so used as to include adjectives, as being descriptive; but in general it is limited to substantives.

Source: Webster's Revised Unabridged Dictionary (1913)