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 the performers, the ceremony will honor Warren Zevon with the Musical Influence Award, and key behind-the-scenes figures like Thom Bell, Nicky Hopkins, and Carol Kaye with the Musical Excellence Award. —Okla Jones, Essence, 28 Apr. 2025

Career coaching now serves as a strategic investment in a student’s future, in addition to what is provided in university. —Nia Bowers, USA Today, 27 Apr. 2025

In addition to the four-course meals attendees enjoyed, guests participated in a live auction, bidding on packages that for many, were hard to pass up. —Kristin L. Wolfe, Forbes.com, 27 Apr. 2025

In addition to his original songs, he was known for his covers, which explains this a bit. —Christian Lewis, Variety, 27 Apr. 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)