English

Alternative forms

• Q.E.D. / Q. E. D.
• (quod erat demonstrandum): q.e.d.

Interjection

QED

1. Quod erat demonstrandum (Latin what had to be proved or what was to be demonstrated).

Usage notes

When used to end a mathematical proof, QED is somewhat archaic or traditional; textbooks often use a graphical symbol instead. Further, other languages generally use a vernacular abbreviation, such as French CQFD ‎(“ce qu'il fallait démontrer”); QED is primarily used in English and Hungarian.

Related terms

• (what was to be demonstrated): QEF

Translations

Noun

QED

1. Quantum electrodynamics.
   • 2011, Brian Cox & Jeff Forshaw, The Quantum Universe, Allen Lane 2011, p. 176:

     QED is the theory that explains how electrically charged particles, like electrons, interact with each other and with particles of light (photons).

Related terms

• (quantum): QCD

Anagrams

• DEQ

Latin

Initialism

QED

1. QED

Portuguese

Etymology

Borrowing from Latin QED.

Interjection

QED

1. (sciences) QED

Synonyms

• CQD