'addition' definitions:

Definition of 'addition'

From: WordNet
noun
A component that is added to something to improve it; "the addition of a bathroom was a major improvement"; "the addition of cinnamon improved the flavor" [syn: addition, add-on, improver]
noun
The act of adding one thing to another; "the addition of flowers created a pleasing effect"; "the addition of a leap day every four years" [ant: deduction, subtraction]
noun
A quantity that is added; "there was an addition to property taxes this year"; "they recorded the cattle's gain in weight over a period of weeks" [syn: addition, increase, gain]
noun
Something added to what you already have; "the librarian shelved the new accessions"; "he was a new addition to the staff" [syn: accession, addition]
noun
A suburban area laid out in streets and lots for a future residential area
noun
The arithmetic operation of summing; calculating the sum of two or more numbers; "the summation of four and three gives seven"; "four plus three equals seven" [syn: summation, addition, plus]

Synonyms of 'addition'

From: Moby Thesaurus