Pronunciation: /ˌʌn.dɪˈfaɪnd/ Explain

A mathematical statement that is meaningless is called undefined. One example of undefined is division by zero. Since division by zero is unbounded, it has no meaning, and so is not interpreted mathematically. So mathematicians say that, 'Division by zero is undefined.'

Any operation on an undefined value is also undefined. Take the two statements a = 5 / 0 and b = 2 · a. Since division by zero is undefined, a is undefined. Because a is undefined, 2 · a is undefined. This means that b must also be undefined.


  1. McAdams, David E.. All Math Words Dictionary, undefined. 2nd Classroom edition 20150108-4799968. pg 183. Life is a Story Problem LLC. January 8, 2015. Buy the book

Cite this article as:

McAdams, David E. Undefined. 5/13/2019. All Math Words Encyclopedia. Life is a Story Problem LLC. https://www.allmathwords.org/en/u/undefined.html.

Revision History

5/13/2019: Changed equations and expressions to new format. (McAdams, David E.)
12/21/2018: Reviewed and corrected IPA pronunication. (McAdams, David E.)
12/16/2018: Removed broken links, updated license, implemented new markup. (McAdams, David E.)
9/15/2008: Added wikipedia to more information. (McAdams, David E.)
3/10/2008: Added vocabulary hot link for operation. (McAdams, David E.)
7/12/2007: Initial version. (McAdams, David E.)

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