What does 'ext.' mean in telephone number?



People sometimes give me phone number like (XXX) XXX XXXX ext. XXX. I was wondering what does this 'ext. XXX' mean?


Posted 2016-02-11T18:43:02.913

Reputation: 143

1extension, a line within the phone system at that number. – user3169 – 2016-02-11T18:44:02.397

Do I dial all the numbers at the same time? – Lii – 2016-02-11T18:45:48.263

You only dial the (XXX) XXX XXXX number. After the call is answered you would say or enter the extension number. – user3169 – 2016-02-11T18:49:17.573


This should be looked up in a dictionary. *ext* or *ext* for example.

– user3169 – 2016-02-11T18:53:40.227

@user3169 - I don't see how your second link would unravel the mystery for a learner who is unfamiliar with this.

– J.R. – 2016-02-11T21:33:54.500

@J.R. Just check the definitions of the words in the list, and you might find the right definition. Then look for something mentioning a "(tele)phone". – user3169 – 2016-02-11T23:52:59.860


@user3169 - Given the context, and the five available options, it's not inconceivable that the "ext." would stand for "extra" (as in, "extra digits"). I'm just trying to look at this like a learner might. Moreover, looking up extension in this same dictionary, it says, "an extra telephone connected to the same line as the main telephone." I'm not sure that that would provide a crystal-clear answer, and I don't think ELL is a bad place to ask for clarification.

– J.R. – 2016-02-12T00:34:30.817



ext. is short for extension which is an internal number used within a PBX systems.
It is usually an additional short number and may or may not be related to the originally dialled number.

The extension number is usually requested and dialled once the caller is inside the local PBX system.

Users within the PBX can call each other by using only the extension number.


Posted 2016-02-11T18:43:02.913

Reputation: 63 575