noun

extension

ik-STEN-shuhn/ɪkˈstenʃn/

An addition that takes something beyond its previous limits.

The new extension adds another room to the house.

Etymology

exLatinout

+tensLatinto stretch

+ionLatinaction or result

The pieces express a “stretching out.” The meaning shifted from the action of extending something to the added portion that makes it longer or larger.

In context

HomeInspire6:43

This is the main part of the loft extension addition that we did.

Inside Tee's £1,900,000 Extension & Renovation Project in North London

More examples

She requests a two-week extension to finish the project.
The .pdf extension identifies the file as a PDF document.
Call my extension if the main line is busy.

Forms

extension · extensions

extend verb — To make longer or reach farther.

Similar words

addition: Anything added, without necessarily going beyond previous limits.
expansion: Emphasizes increased size or scope rather than an added part.