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 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

Army chief Asim Munir will now be elevated to the new post of Chief of Defence Forces, placing the navy and air force under his command in addition to the army. —Reuters, CNN Money, 13 Nov. 2025

In addition, the Cavaliers were without Darius Garland (toe injury management), Max Strus (left foot surgery) and Jaylon Tyson (concussion) against the Heat. —Anthony Chiang, Miami Herald, 13 Nov. 2025

In addition to the full 700 ml bottle, a limited number of 100 ml decanters, presented in an elegant green keepsake case, will be available for $630. —Robb Report Studio, Robb Report, 13 Nov. 2025

In addition to Preston, the series also stars Wendell Pierce. —Clayton Davis, Variety, 12 Nov. 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)