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

Phrases

in addition

: besides entry 2, also

The job requires a college degree and, in addition, at least two years of experience.

in addition to

: combined or associated with : besides entry 1 sense 2

In addition to soup, several salads were served.

Synonyms

• 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

In addition to Labubus, the trading cards collectible category is surging, according the StockX. Sales of Pokemon cards are up 367% in the first half of the year and sales of Topps cards are up 208%. —Joan Verdon, Forbes.com, 13 Aug. 2025

In addition to sketch comedy, the company is responsible for numerous podcasts. —Matt Grobar, Deadline, 13 Aug. 2025

In addition to its standard weekend brunch, Buckatabon will serve breakfast from 8 to 11 a.m. Monday to Friday while Hollander is closed. —Rachel Bernhard, jsonline.com, 13 Aug. 2025

Because Florida law provides for the prevailing party to also be awarded court costs and attorney’s fees in addition to any damages in such matters, the association will now likely be on the hook for the owner’s legal costs as well as its own, both presumably fairly substantial. —Laura Manning-Hudson, Miami Herald, 13 Aug. 2025

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)