The Meaning of QED: What It Is and How To Use It

Do you know the definition of QED? This article will provide you with all of the information you need on the acronym QED, including its definition, usage, examples, and more!

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What does the acronym QED stand for?

According to Cambridge English Dictionary, Dictionary, and Cornell Law, the acronym QED usually stands for the Latin phrase quod erat demonstrandum, which translated to “which was to be demonstrated.” This abbreviation, which is sometimes spelled out as Q.E.D., usually appears at the end of a conclusion to some essay or other text that signifies that the author’s argument has been proven. Ancient Greek mathematicians used to place this term as the end of logical proofs. By the early 20th century, the term QED breached out of math and philosophy in a more general way to mean therefore, or thus. This is most commonly used in scholarly settings. This is considered an initialism, which means that each letter is pronounced individually. Therefore, the abbreviation Q.E.D. would be pronounced “ˌkjuːiːˈdiː.” Try using this word of the day or other new words in a sentence today!

Many other languages also use their own abbreviations for the term QED. You may notice that some of these abbreviations look similarly to each other. THis is likely because they share a common origin or root. Often words that look sound and mean the same thing across languages, called cognates, are formed when the languages or words share a common ancestral language like Latin or Greek. This list of translations for the acronym QED is provided by Word Sense.

  • German: w. z. b. w.‎ (was zu beweisen war)
  • Greek: Ό.Έ.Δ.‎ (όπερ έδει δείξαι)
  • Vietnamese: đpcm‎
  • Italian: (come volevasi dimostrare) CVD‎
  • Russian: ч. т. д.‎, что и тре́бовалось доказа́ть‎ (što i trébovalosʹ dokazátʹ)
  • Chinese – Mandarin: 證畢‎, 证毕‎ (zhèngbì), 證訖‎, 证讫‎ (zhèngqì)
  • Esperanto: KEP‎ (kio estis pruvota)
  • Portuguese: CQD‎, QED‎
  • Slovak: (čo bolo treba dokázať) Č.B.T.D.‎
  • French: CQFD‎ (ce qu’il fallait démontrer)
  • Finnish: MOT‎ (mikä oli todistettava)
  • Hindi: इ. सि.‎ (इति सिद्धम्)
  • Swedish: VSV‎ (vilket skulle visas), VSB‎ (vilket skulle bevisas)
  • Polish: c.b.d.o.‎, c.b.d.u.‎
  • Icelandic: þ.s.s.á.‎ (það sem sanna átti)
  • Georgian: რ.დ.გ‎
  • Spanish: C.Q.D.‎, (written out) como queríamos demostrar‎
  • Japanese: 証明終わり‎ (しょうめいおわり, shōmei owari)
  • Hebrew: מָשָׁ”ל‎ (masha”l), מ.ש.ל.‎ (מה שצריך להוכיח , מה שרצינו להוכיח , etc.)
  • Czech: c.b.d.‎ (co bylo dokázat)

According to The Free Dictionary, the acronym QED can mena much more than just the Latin phrase. However, these alternate definitions are far less common. If you do decide to use one of these alternate definitions, make sure that you provide the reader with the proper context so that they can infer the correct meaning. This should be standard practice for any acronym that has more than one possible definition. 

  • Quick Easy Disk
  • Quinn Elicits Dismay
  • Quantum Electronic Devices (physics; various organizations)
  • Quantitative Enterprise Development
  • Quick Editor
  • Quality Evaluation for Dismantlement
  • Quadcap Embeddable Database
  • Quality Engineering Directorate
  • Quality Education @ A Distance (AU)
  • Queues Enforth Development, Inc.
  • Quick Epicenter Determination(s) (USGS)
  • Qualifying Educational Data
  • Quantitative Economics Doctorate
  • Question Everything Done
  • Quantum Electro Dynamics
  • Quickly and Easily Done (Colloquial: Mathematical proofs)
  • Quite Easily Done
  • Quantum Explosion Dynamo (gaming)
  • Quality Editor
  • Quickly Ends Dandruff
  • Quintain Estates and Development (UK)
  • Quest Engineering Development
  • Queen’s Economics Department (Queen’s University Kingston, ON, Canada)
  • Quilting Engineering Divas
  • Quantum Economic Development
  • Qualitative European Drug Research
  • Quick and Easy Drawings
  • Quicktime for Education
  • Quality Engineer Division
  • Queen Elizabeth Drive
  • Quest for Economic Development (UK)
  • Quality Education Data, Inc.
  • Quantum Effects Devices
  • Quantum Electrodynamics
  • Quality Education Data
  • Quest Enabling Designs Ltd. (UK)
  • Quechua, Ancash, Conchucos, Northern (SIL code, Peru)
  • Quantum Effect Design

What are synonyms for the term Q.E.D.?

There are many different words and phrases that one can use in place of the term QED, particularly in its modern usage. Today, most people use this term to mean therefore or thus. Many people do not know what QED stands for, so it is often better to find a synonym or one of a list or other related words and use that instead, Synonyms are also useful to know if you want to avoid repeating yourself as well as if you are looking to expand your vocabulary. This list of alternate words is provided by Thesaurus.

  • like this
  • then
  • so
  • in consequence
  • in that event
  • whence
  • along these lines
  • in respect to
  • thus
  • just like that
  • resultantly
  • suitably
  • thusly
  • ergo
  • in this way
  • consequently
  • appropriately
  • subsequently
  • therefrom
  • hence
  • correspondingly
  • properly
  • as follows
  • duly
  • respectively
  • thus and so
  • to such a degree
  • therefore
  • in this fashion
  • wherefore
  • and so
  • for this reason
  • under the circumstances
  • fitly
  • forasmuch as
  • in kind
  • on account of
  • inasmuch as
  • equally
  • thereupon
  • like so
  • thence
  • to that end
  • since
  • accordingly
  • proportionately
  • thus and thus
  • as a consequence
  • in such a way
  • on the grounds
  • as a result
  • for

Overall, the abbreviation Q.E.D. stands for the Latin quod erat demonstrandum which means “which was to be demonstrated.” Mathematicians and philosophers use this phrase at the end of a mathematical proof or theorem, or at the end of an essay or argument, to signal that their point has been proven. In American English, this term is usually used in scholarly works. This term is used most frequently in modern English to mean therefore or thus. Since many people may be unfamiliar with the term QEd, it is often better to find a synonym or replacement. Otherwise, one can opt to use the full form of the phrase quod erat demonstrandum.