Definition of quod erat demonstrandum in English:

Share this entry

quod erat demonstrandum

Pronunciation: /kwɒd ˌɛrat dɛmənˈstrandʊm/
(abbreviation QED)


Used to convey that a fact or situation demonstrates the truth of one’s theory or claim, especially to mark the conclusion of a formal proof.


Latin, literally 'which was to be demonstrated'.

For editors and proofreaders

Line breaks: quod erat dem¦on|stran¦dum

Share this entry

What do you find interesting about this word or phrase?

Comments that don't adhere to our Community Guidelines may be moderated or removed.