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QED

1 American  

abbreviation

Physics.

  1. quantum electrodynamics.

Q.E.D. 2 American  

abbreviation

  1. which was to be shown or demonstrated (used especially in mathematical proofs).

QED British  

abbreviation

  1. quod erat demonstrandum

  2. quantum electrodynamics

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Etymology

Origin of Q.E.D.

First recorded in 1810–20, Q.E.D. is from Latin quod erat dēmōnstrandum

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

In the electron's reference frame, the laser intensity appeared to be about 50% of the Schwinger limit, triggering nonlinear QED phenomena.

From Science Daily • Nov. 25, 2024

The attorney general accuses Steen and Fichtenbaum of ”backdoor ties” to QED.

From Seattle Times • May 24, 2024

"Any fintech with serious, long-term ambitions will likely have to find a way to become a bank," says Mike Packer, an investor at QED, a venture capital fund which has backed several lending fintechs.

From Reuters • Oct. 17, 2022

It produced its first commercial MRI machine, QED 80, in 1980.

From Washington Post • Aug. 18, 2022

QED: quod erat demonstrandum, Latin for “which was to be demonstrated or proved.”

From "Charles and Emma: The Darwins' Leap of Faith" by Deborah Heiligman

Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.