Webster's Revised Unabridged Dictionary · 1913

Noun

Noun (noun) , noun

[Old French noun, nun, num, non, nom, French nom, from Latin nomen name. See Name.]

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

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