Addition

n. act of joining one thing to another; basic mathematical operation in which separate numbers are brought together into one total sum; augmentation, supplement, something added

Addition is the mathematical operation of combining or adding two numbers to obtain an equal simple amount or total. Addition also provides a model for related processes such as joining two collections of objects into one collection. Repeated addition of the number one is the most basic form of counting.
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Noun
1. a component that is added to something to improve it; "the addition of a bathroom was a major improvement"; "the addition of cinammon improved the flavor"
(synonym) add-on, improver
(hypernym) component, constituent, element
(hyponym) additive
(derivation) lend, impart, bestow, contribute, add, bring
2. 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"
(antonym) subtraction, deduction
(hypernym) increase, step-up
(hyponym) retrofit
(derivation) add
3. 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"
(synonym) increase, gain
(hypernym) indefinite quantity
(hyponym) accretion
4. something added to what you already have; "the librarian shelved the new accessions"; "he was a new addition to the staff"
(synonym) accession
(hypernym) acquisition
5. a suburban area laid out in streets and lots for a future residential area
(hypernym) suburb, suburbia, suburban area
6. 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"
(synonym) summation, plus
(hypernym) arithmetic operation
(derivation) total, tot, tot up, sum, sum up, summate, tote up, add, add together, tally, add up

n. addition, act of joining one thing to another; basic mathematical operation in which separate numbers are brought together into one total sum; augmentation, supplement, something added

n. addition, sum; bill, check; reckoning; summary, summing up; tab