Definitions
from The American Heritage® Dictionary of the English Language, 5th Edition.
 abbreviation Latin quod erat demonstrandum (which was to be demonstrated)
from the GNU version of the Collaborative International Dictionary of English.
 noun abbreviated Quantum electrodynamics.
from Wiktionary, Creative Commons Attribution/ShareAlike License.
 interjection
Quod erat demonstrandum (Latin what had to be proved or what was to be demonstrated).  noun
Quantum electrodynamics .
Etymologies
from Wiktionary, Creative Commons Attribution/ShareAlike License
Examples

Coulomb's law is governed by the magnitude of the vertex which is the electric charge e in QED and for the diagram above it is proportional to the square of e and is the Fine Structure Constant = 1/137.

Calculations starting from this picture have reproduced the experimental data by Kusch and Lamb to an astonishing degree of accuracy and modern QED is now considered to be the most exact theory in existence.

This progress in QED turned out to be of the greatest importance also for the description of phenomena at higher energies.

So saying that field theory is sometimes called QED, is like saying algebra is sometimes called the quadratic equation.

So saying that field theory is sometimes called QED, is like saying algebra is sometimes called the quadratic equation.

So saying that field theory is sometimes called QED, is like saying algebra is sometimes called the quadratic equation.

So saying that field theory is sometimes called QED, is like saying algebra is sometimes called the quadratic equation.

It was then that Ms. Meyer and Ms. Flemal decided to start a homeschooling education service called QED (Quality Education by Design), a consulting firm that pairs parents of children in preK through middle school with private teachers.
Watch Out, GVHS: At New UltraPrivate School, Your Kid's the Only Student!

Then the independent sales company, called QED, went to the American Film Market in Santa Monica, and they were able to raise the money from preselling rights to the movie, to independent distributors around the world.

It was then that Ms. Meyer and Ms. Flemal decided to start a homeschooling education service called QED (Quality Education by Design), a consulting firm that pairs parents of children in preK through middle school with private teachers.
alexz commented on the word QED
QED is too passive.
From now on, I will end my proofs with ita ibi*
(*so there)
February 8, 2013