addition

noun

ad·​di·​tion ə-ˈdi-shən 

a-

1

: a part added (as to a building or residential section)

The addition expanded the kitchen.

2

: anything or anyone added : increase

The clerk was a recent addition to the staff.

3

: the act or process of adding

a recipe enhanced by the addition of freshly ground pepper

especially : the operation of combining numbers so as to obtain an equivalent simple quantity

schoolchildren learning about addition and subtraction

4

: direct chemical combination of substances into a single product

see also in addition, in addition to

Synonyms of addition

• extension
• annex

Examples of addition in a Sentence

The children learned addition and subtraction.

The museum's collection includes several new additions.

Recent Examples on the Web

At the same time, Jamie Krents has been promoted to President and CEO of UMe, in addition to his current role as President and CEO of UMG’s Verve Label Group. —Jem Aswad, Variety, 3 Feb. 2026

Forward Vieira, on a season’s loan from Arsenal, produced all sorts of craft throughout, in addition to nervelessly converting that penalty. —Sebastian Stafford-Bloor, New York Times, 3 Feb. 2026

The talent competition will air live on the streamer for the first time, in addition to airing on ABC. —Peter White, Deadline, 3 Feb. 2026

In addition, Dana Walden, who currently leads the studios segment, has been promoted to President and Chief Creative Officer, also effective in March. —Brian Welk, IndieWire, 3 Feb. 2026

Word History

Etymology

Middle English addicioun, borrowed from Anglo-French addicion, borrowed from Latin additiōn-, additiō, from addi-, variant stem of addere "to add" + -tiōn-, -tiō, suffix of action nouns

First Known Use

14th century, in the meaning defined at sense 1

Rhymes for addition

• admission
• ambition
• attrition
• audition
• clinician
• cognition
• coition
• commission
• condition
• contrition
• dentition
• dismission

Kids Definition

addition

noun

ad·​di·​tion ə-ˈdish-ən 

a-

1

: the result of adding : increase

2

: the act, process, or operation of adding

3

: a part added (as to a building)