from The American Heritage® Dictionary of the English Language, 5th Edition.

  • noun The operation that, for positive integers, consists of increasing by a definite number of increments of 1. The operation is extended to other numbers according to the additive properties of positive integers and other algebraic properties.
  • noun Any of certain analogous operations involving mathematical objects other than numbers.
  • noun The process of adding or joining something to something else, typically to make it larger.
  • noun Something added.
  • idiom (in addition) Also; as well.
  • idiom (in addition to) Over and above; besides.

from The Century Dictionary.

  • noun The act or process of adding or uniting, especially so that the parts remain independent of one another: opposed to subtraction or diminution: as, a sum is increased by addition; to increase a heap by the addition of more.
  • noun The result of adding; anything added, whether material or immaterial.
  • noun Specifically— In law, a title or designation annexed to a man's name to show his rank, occupation, or place of residence: as, John Doe, Esq.; Richard Roe, Gent.; Robert Dale, Mason; Thomas Way, of Boston, Hence—
  • noun An epithet or any added designation or description: a use frequent in Shakspere, but now obsolete.
  • noun In music, a dot at the side of a note indicating that its sound is to be lengthened one half.
  • noun In heraldry, same as augmentation.
  • noun In distilling, anything added to the wash or liquor when in a state of fermentation.
  • noun Superaddition, appendage, adjunct, increase, increment, extension, enlargement, augmentation.
  • To furnish with an addition, or a designation additional to one's name.
  • To combine; add together.

from the GNU version of the Collaborative International Dictionary of English.

  • noun The act of adding two or more things together; -- opposed to subtraction or diminution.
  • noun Anything added; increase; augmentation.
  • noun (Math.) That part of arithmetic which treats of adding numbers.
  • noun (Mus.), rare A dot at the right side of a note as an indication that its sound is to be lengthened one half.
  • noun (Law) A title annexed to a man's name, to identify him more precisely.; Richard Roe, Gent.; Robert Dale, Mason; Thomas Way, of New York; a mark of distinction; a title.
  • noun (Her.) Something added to a coat of arms, as a mark of honor; -- opposed to abatement.
  • noun (Geom.) that kind of addition of two lines, or vectors, AB and BC, by which their sum is regarded as the line, or vector, AC.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

  • noun uncountable The act of adding anything.
  • noun Anything that is added.
  • noun uncountable The arithmetic operation of adding.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

  • noun a quantity that is added
  • noun a suburban area laid out in streets and lots for a future residential area
  • noun a component that is added to something to improve it
  • noun the act of adding one thing to another
  • noun something added to what you already have
  • noun the arithmetic operation of summing; calculating the sum of two or more numbers


from The American Heritage® Dictionary of the English Language, 4th Edition

[Middle English, from Old French, from Latin additiō, additiōn-, from additus, past participle of addere, to add; see add.]

from Wiktionary, Creative Commons Attribution/Share-Alike License

Sense of “what is added” dating from 14th Century CE; from Old French adition ("increasement"), from Latin additiōnem, accusative singular of additio.


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