Definition of addition

• 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"
• 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"
• a quantity that is added; "there was an addition to property taxes this year"; "they recorded the cattles gain in weight over a period of weeks"