Cambridge Dictionaries online Cambridge Dictionaries online

The most popular online dictionary and thesaurus for learners of English

English definition of “extension”

See all translations

extension

noun  /ɪkˈsten·ʃən/ us  

extension noun (PHONE)

[C] ( abbreviation ext.) any of two or more telephones in the same house that share the same number: We have an extension in our bedroom. [C] ( abbreviation ext.) An extension is also any of the telephones connected to a central system, esp. in a business.

extension noun (ADDITION)

[C/U] an amount by which something is increased, or something added to something else: a contract extension I applied for an extension to my visa. [C] We’re building an extension on our house to enlarge the kitchen.
(Definition of extension from the Cambridge Academic Content Dictionary © Cambridge University Press)
What is the pronunciation of extension?
Add Cambridge dictionaries to your browser to your website

More American English definitions for “extension”

Definitions of “extension” in other dictionaries

Word of the Day

be as cold as ice

to be extremely cold

Word of the Day

Let’s celebrate! (words and phrases for parties)

by Kate Woodford,
December 17, 2014
​​​ With Christmas and New Year almost upon us, we thought it a good time to look at the language of parties and celebrations. First, let’s start with the word ‘party’ itself. To have or throw a party or, less commonly, to give a party is to arrange a party: We’re having a

Read More 

cinderella surgery noun

December 15, 2014
cosmetic surgery to the feet We have all heard of people having nose jobs, boob jobs and liposuction – but now a new trend growing in popularity in America: Cinderella surgery.

Read More