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

• annex
• extension
• penthouse

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 access to on-demand content, the Audible subscription gives you one credit per month to buy any audiobook from the entire catalog. —Clint Davis, People.com, 22 Mar. 2025

But in addition to flowers, April showers can also bring a lot of joint pain. —Elizabeth Medeiros, Health, 22 Mar. 2025

The stealth nature and structure of the agreement in addition to the comments made by Caesars and Icahn strongly indicate that this is a very amicable arrangement, and that Icahn is confident in management’s ability. —Kenneth Squire, CNBC, 22 Mar. 2025

In addition to its historical importance, the site provides a boost to the small town of Petersburg just to the north, said David Blanchette, a local journalist who has been involved in area museums including the Abraham Lincoln Presidential Library and Museum in Springfield. —Addison Wright, Chicago Tribune, 22 Mar. 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)