1. The act of adding two or more things together; opposed to subtraction or diminution. "This endless addition or addibility of numbers."

2. Anything added; increase; augmentation; as, a piazza is an addition to a building.

3. <mathematics> That part of arithmetic which treats of adding numbers.

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

5. 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. Something added to a coat of arms, as a mark of honor; opposed to abatement.

<geometry> Vector addition, that kind of addition of two lines, or vectors, AB and BC, by which their sum is regarded as the line, or vector, AC.

Synonyms: Increase, accession, augmentation, appendage, adjunct.

Origin: F. Addition, L. Additio, fr. Addere to add.

(01 Mar 1998)