definition of
addition

[1] #1 addition n. [add-on, improver] 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". wn

[2] #2 addition n. 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". wn

[3] #3 addition n. [increase, gain] 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". wn

[4] #4 addition n. [accession] something added to what you already have; "the librarian shelved the new accessions"; "he was a new addition to the staff". wn

[5] #5 addition n. a suburban area laid out in streets and lots for a future residential area. wn