postfix, n. [Pref. post- + -fix, as in prefix: cf. F. postfixe.].
A letter, syllable, or word, added to the end of another word; a suffix. Parkhurst. [1913 Webster]
postfix, v. t.
To annex; specifically (Gram.), to add or annex, as a letter, syllable, or word, to the end of another or principal word; to suffix. Parkhurst. [1913 Webster]