(1):

(n.) Anything added; increase; augmentation; as, a piazza is an addition to a building.

(2):

(n.) The act of adding two or more things together; - opposed to subtraction or diminution.

(3):

(n.) That part of arithmetic which treats of adding numbers.

(4):

(n.) A dot at the right side of a note as an indication that its sound is to be lengthened one half.

(5):

(n.) A title annexed to a man's name, to identify him more precisely; as, John Doe, Esq.; Richard Roe, Gent.; Robert Dale, Mason; Thomas Way, of New York; a mark of distinction; a title.

(6):

(n.) Something added to a coat of arms, as a mark of honor; - opposed to abatement.