noun.
A word, phrase, or clause that limits or qualifies the sense of another word or word group.
The Century Dictionary and Cyclopedia
noun.
One who or that which modifies.
the GNU version of the Collaborative International Dictionary of English
noun.
One who, or that which, modifies.
noun.
A word or phrase that modifies another word, phrase, or sentence, usually by limiting the scope or restricting the meaning of the sentence element modified.