right anglen.
/ˈrʌɪt ˌaŋɡl/, U.S. /ˈraɪd ˌæŋɡ(ə)l/ 1. Chiefly Geometry. An angle of ninety degrees; spec. one formed by two perpendicular lines, as in the corner of a square or in a quartered circle.
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the world > space > shape > angularity > [noun] > angle or corner > right angle
right anglec1400
right corner1548
rectangle1560
quadrate1568
straight angle1601
the world > relative properties > number > geometry > angle > [noun] > right angle
right anglec1400
rectangle1560
quadrate1568
straight angle1601
rect angle1605
c1400 ( G. Chaucer Treat. Astrolabe (Brussels) (1940) ii. §26. f. 91 This..riȝt [v.r. rethe] orizont..diuideth the equinoxial in to riȝt [v.r. rothes] angles.
1551 R. Record Pathway to Knowl. i. Defin. A blunt or brode corner is greater then is a square angle, and his lines do parte more in sonder then in a right angle.
1669 S. Sturmy Mariners Mag. iii. ii. 129 Because the Angle cab is a Right Angle,..I therefore only put an Unity before the second Term.
1726 J. Swift Gulliver II. iii. ii. 26 Their Houses are very ill built, the Walls Bevil, without one Right Angle in any Apartment.
1834 Nat. Philos. (Libr. Useful Knowl.) III. Navigation i. i. 2 The side ab, opposite to the right angle, is called the hypotenuse.
1880 W. MacCormac Antiseptic Surg. 11 The right leg was at a right angle with the thigh when the limb was extended.
1931 G. le Q. Martel In Wake of Tank 84 A turn through to a right angle absorbed so much power in skidding the track round that it was usually necessary to change down to first gear.
1998 J. L. Heilbron Geom. Civilized ii. 54 Two right triangles..have one equal part, namely the right angle, but they need have no other parts equal.
2. at right angles (also †in right angles, †in right angle): perpendicularly (to a line, plane, etc.); so as to form an angle of 90 degrees.
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the world > space > relative position > position at right angles to something > at right angles [phrase]
at right angles?a1425
in a square?a1560
by equiangles1593
in right angle1687
on (also upon) the square1883
?a1425 tr. Guy de Chauliac Grande Chirurgie (N.Y. Acad. Med.) f. 15v Musclez bene made in þe wombe..viz,..2 latitudinalez fro þe backe vp þe wombe kuttyng þam bi þe middes of þe wombe at riȝt anglez.
1571 T. Digges in L. Digges's Geom. Pract.: Pantometria xxi. sig. Cc.iij His three diameters crosse them selues at right angles vpon the center of his spheres.
1625 N. Carpenter Geogr. Delineated i. ix. 205 The Sunne darts forth his Rayes at right Angles, which reflect backe vpon themselues.
1687 A. Lovell tr. J. de Thévenot Trav. into Levant ii. 145 There are six figures on each side..and as many on the border in right Angle.
1718 J. Ozell tr. J. Pitton de Tournefort Voy. Levant II. 216 Cottages,..the four Walls whereof are made of Pines, rang'd pointways in right Angles one upon another.
1746 Tom Thumb's Trav. Eng. 114 Most of the Streets..cut one another at Right Angles.
1804 G. Cayley in J. L. Pritchard Sir G. Cayley (1961) 220 An horizontal and vertical surface..intersecting each other in right angles to the air.
1837 J. G. Lockhart Mem. Life Scott III. iii. 128 [His] residence was then in George Street, situated very near to, and at right angles with, North Castle Street.
1890 Cent. Mag. May 51/2 Narrow black lines at right angles to the shaft of the feather.
1935 C. J. Smith Intermediate Physics (ed. 2) v. xlviii. 805 The arc lamp consists essentially of two carbon rods, generally at right angles to one another.
2005 Woodworker May 106/2 Two secret drawers which open at right angles to the outgoing deep drawers.
Compounds
right-angle fold n. Printing a fold set at right angles to another.
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society > communication > printing > post-printing processes > [noun] > fold of sheet
right-angle fold1915
society > communication > book > manufacture or production of books > book-binding > [noun] > fold at right angles to previous fold
right-angle fold1915
1915 H. W. Hess Productive Advertising ix. 125 Sixteen pages is the most economical number, for it takes three right angle folds and makes a better and cheaper book than one of twelve or twenty pages.
1931 H. Jahn Hand Composition xvi. 264 Models..which operate at high speed on both parallel and right-angle fold work.
2001 Graphic Arts Monthly (Nexis) 1 Oct. 39 We also use them [sc. Stahl folders] to produce accordion folds for our oblong books, right-angle folds for our upright books, [etc.].
right-angle folding n. Printing the action or process of making right-angle folds.
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1925 B. L. Goodwin Pamphlet Binding 16 There is..a tendency for the inside sheets to pucker up at the corner folds when right-angle folding is done.
1946 A. Monkman in H. Whetton Pract. Printing & Binding v. 59 Machines are available to fold large and small sheets and for parallel or right-angle folding.
2001 Graphic Arts Monthly (Nexis) 1 June 74 The folder also..is a lot easier and quicker to set up and is more operator-friendly—even with all the right-angle folding we do.
right-angle prism n. Optics a prism whose cross-section is a right triangle, used for deflecting rays through 90 degrees (if they enter through one of the faces forming the right angle) or 180 degrees (if they enter through the hypotenuse face).
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1871 Eng. Mechanic 31 Mar. 42/3 I have also taken photos of the sun with the same telescope, only fixing the right-angle prism..between the object-glass and the terrestrial combination.
1923 C. E. Dull Essent. Mod. Physics xviii. 297 The right-angle prism is more efficient as a reflector than a mirror would be if set in the same position.
1997 G. Smith & D. A. Atchison Eye & Visual Optical Instruments viii. 195 The right-angle prism is used for deviating the beam through 90°.
This entry has been updated (OED Third Edition, June 2010; most recently modified version published online March 2022).
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