An addition is the act of adding something new, like a baby — a new addition to your family — or what you do in math class: the addition of columns of numbers to get the sum.

The noun addition comes from the Old French word adition, meaning "that which is added." A new room built onto your house, a new item in a store's inventory, even another baseball cap in your collection — all of these are additions. Usually thought of as improvements, you may have heard the phrase "welcome addition" to describe a new cast mate to a television show that has lost its creative spark or a new ball field at your local park.

Definitions of addition
  1. noun
    the arithmetic operation of summing; calculating the sum of two or more numbers
    synonyms: plus, summation
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    type of:
    arithmetic operation
    a mathematical operation involving numbers
  2. 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”
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    deduction, subtraction
    the act of subtracting (removing a part from the whole)
    the act of adding a component or accessory to something that did not have it when it was manufactured
    fluoridation, fluoridisation, fluoridization
    the addition of a fluoride to the water supply (to prevent dental decay)
    type of:
    increase, step-up
    the act of increasing something
  3. noun
    a quantity that is added
    “there was an addition to property taxes this year”
    synonyms: gain, increase
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    something contributing to growth or increase
    type of:
    indefinite quantity
    an estimated quantity
  4. 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”
    synonyms: add-on, improver
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    something added to enhance food or gasoline or paint or medicine
    an addition that was not included in the original plan
    annex, annexe, extension, wing
    an addition that extends a main building
    a supplementary part or accessory
    elongation, extension
    an addition to the length of something
    a thing that is added or will be added
    an additive that enhances the effectiveness of medical treatment
    an extension at the end and at right angles to the main building
    artificial additive, food additive
    an additive to food intended to improve its flavor or appearance or shelf-life
    hood, lens hood
    a tubular attachment used to keep stray light out of the lens of a camera
    type of:
    component, constituent, element
    an artifact that is one of the individual parts of which a composite entity is made up; especially a part that can be separated from or attached to a system
  5. noun
    something combined with what you already have
    “he was a new addition to the staff”
    synonyms: accession
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    type of:
    something acquired
  6. noun
    a suburban area laid out in streets and lots for a future residential area
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    type of:
    suburb, suburban area, suburbia
    a residential district located on the outskirts of a city
Word Family

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