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English definition of “addition”

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addition

noun uk   /əˈdɪʃ.ən/ us  
B2 [U] the process of adding numbers or amounts together: Twice a week the children are tested in basic mathematical skills such as addition (= calculating the total of different numbers put together) and subtraction.in addition (to) B1 as well (as): In addition to his apartment in Manhattan, he has a villa in Italy and a castle in Scotland.B2 [C] something that has been added to something else: A secretary would be a welcome/useful addition to our staff. humorous I hear you're expecting a small addition to the family (= you are going to have a baby)! [C] the act of adding a substance or thing to something else: Most working environments are improved by the addition of (= by adding) a few plants and pictures. [C] US ( UK extension) a new part added to a house or other building: We're building an addition to our house.
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(Definition of addition from the Cambridge Advanced Learners Dictionary & Thesaurus © Cambridge University Press)
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