- The definition of addition is the process of bringing two or more numbers or things together.
Calculating the sum of 25 and 60 is an example of addition.
A child does addition problems on the blackboard.
addition definition by Webster's New World
- an adding of two or more numbers to get a number called the sum
- a joining of a thing to another thing
- a thing or part added; increase; specif., a room or rooms added to a building
- Law an identifying title or mark of status after a person's name (Ex.: John Smith, Esq.)
Origin: Middle English addicion ; from Old French addition ; from Classical Latin additio ; from addere: see add
addition definition by American Heritage Dictionary
- The act or process of adding, especially the process of computing with sets of numbers so as to find their sum.
- Something added, such as a room or section appended to a building.
Origin: Middle English, from Old French, from Latin additiō, additiōn-, from additus, past participle of addere, to add; see add.
- ad·diˈtion·al adjective
- ad·diˈtion·al·ly adverb
addition - Phrases/Idioms
in addition (to)
in addition to
addition - Science Definition