Q. E. D.

Q. E. D.

1. Alternative form of Q.E.D. (“initialism of quod erat demonstrandum”)
   • 1759, [Laurence Sterne], chapter XIX, in The Life and Opinions of Tristram Shandy, Gentleman, 2nd (1st London) edition, volume II, London: R and J Dodsley , published 1760, →OCLC, page 168:

     If death, ſaid my father, reaſoning with himſelf, is nothing but the ſeparation of the ſoul from the body;—and if it is true that people can walk about and do their buſineſs without brains,—then certes the ſoul does not inhabit there. Q. E. D.

   • 1775, Benjamin Donn, “An Essay on Plane Geometry”, in The Geometrician: Containing Essays on Plane Geometry, and Trigonometry: , 2nd edition, London: Sold by J Johnson, , →OCLC, book I (The Introduction), paragraph 59, page 10:

     Theorem 2. The Angles ${\displaystyle B}$, ${\displaystyle C}$, at the Baſe of an Iſoceles Triangle ${\displaystyle ABC}$, are equal to each other; and a Line ${\displaystyle AD}$ biſecting the Angle ${\displaystyle BAC}$, divides the Baſe into two equal Parts, and is perpendicular thereto. For becauſe the Line ${\displaystyle AD}$ biſects the ${\displaystyle \angle A}$, that is, makes the ${\displaystyle \angle BAD=\angle CAD}$, and Side ${\displaystyle AB}$ is ${\displaystyle =AC}$, and ${\displaystyle AD}$ common to both, the ${\displaystyle \triangle ABD=\triangle ACD}$; ${\displaystyle \angle B=\angle C}$, and ${\displaystyle \angle ADB=\angle ADC}$; ${\displaystyle \because AD\perp }$ to ${\displaystyle BC}$. Q. E. D.

   • 1818 July 25, Jedadiah Cleishbotham [pseudonym; Walter Scott], chapter VI, in Tales of My Landlord, Second Series,  (The Heart of Mid-Lothian), volume IV, Edinburgh: [James Ballantyne and Co.] for Archibald Constable and Company, →OCLC, page 120:

     Ergo, Reuben Butler might take possession of the parish of Knocktarlitie, without forfeiting his friendship or favour—Q. E. D.

   • 1823, Daniel Waterland, “A Second Defence of Some Queries Relating to Dr. Clarke’s Scheme of the Holy Trinity: In Answer to the Country Clergyman’s Reply”, in The Works of the Rev. Daniel Waterland, D.D. , volume III, Oxford, Oxfordshire: At the Clarendon Press, →OCLC, query III, page 165:

     [I]f the Son [of God] be in nature equal to the Father, he is also equal in Godhead, which is a word expressing nature; and if equal in Godhead, equally God supreme. Q. E. D.

Q. E. D.

1. Alternative form of Q.E.D. (“some fact or scenario that proves an argument or proposition”)
   • 1814 February, G. D. Yeats, “Account of Ann Fooks’s Case of Ischuria and Vomiting of Urine”, in Samuel Fothergill, John Want, editors, The Medical and Physical Journal, volume XXXI, part 2, number 180, London: Published for the proprietors, by J. Adlard, ; and sold by J. Souter, , →OCLC, page 122:

     This was exactly the Q. E. D. of the paper.

   • 1825, William Magee, “Supplement to the Remarks on the Unitarian Version of the New Testament”, in Discourses and Dissertations on the Scriptural Doctrines of Atonement & Sacrifice; , volume II, Philadelphia, Pa.: S. Potter & Co. ; Jesper Harding, printer, →OCLC, footnote, page 266:

     The Unitarian might therefore here easily produce his Q. E. D. for the exclusion of all but the maintainers of Christ's proper humanity from the pale of Christianity.

   • 1827, “Anglicanus” , “Letter III”, in View of the Character, Position, and Prospects, of the Edinburgh Bible Society. In Seven Letters, Edinburgh: Printed for Brown & Wardlaw, ; and sold by M. Ogle, , →OCLC, page 24:

     Whoever starts a doubt as to the validity of any of those allegations to which he has set his Q. E. D. is indicted as a disturber of the peace.

• DEQ