isoscelesadj.n.
/ʌɪˈsɒsɪliːz/ Geometry.
Of a triangle: Having two of its sides equal. (Formerly sometimes as n.: An isosceles triangle.)
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the world > relative properties > number > geometry > shape or figure > [adjective] > two-dimensional > triangular > isosceles
isosceles1551
tway-like1551
equicrure1644
equicrural1650
isoscelar1711
isoscel1715
1551 R. Record Pathway to Knowl. B iij There is also an other distinction of the names of triangles, according to their sides, whiche other be all equal..other els two sydes bee equall and the thyrd vnequall, which the Greekes call Isosceles, the Latine men æquicurio, and in english tweyleke may they be called.
?a1560 L. Digges Geom. Pract.: Pantometria (1571) i. Defs. sig. B iij Isoscheles is such a Triangle as hath onely two sides like, the thirde being vnequall, and that is the Base.
1570 H. Billingsley tr. Euclid Elements Geom. i. f. 4v Isosceles, is a triangle, which hath onely two sides equall.
1656 T. Stanley Hist. Philos. II. v. 72 The element of a Cube is an Isosceles triangle, for foure such triangles concurring make a square, and six squares a Cube.
1674 N. Fairfax Treat. Bulk & Selvedge 115 We are born in hand with this, That then a Scalenum and Isosceles would be all one.
1798 Anti-Jacobin 7 May 205/1 'Twas thine alone, O Youth of Giant Frame, Isosceles! that rebel heart to tame!
1802 Count de Bournon in Philos. Trans. (Royal Soc.) 92 307 With isosceles triangular planes.
1812 J. Playfair Outl. Nat. Philos. I. 83 The resistance to the motion of an isosceles wedge.
Derivatives
iˈsoscelesism n. the character of being isosceles.Apparently an isolated use.
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1851 J. Ruskin Stones of Venice I. xxi. 249 But the spirit of the triangle must be put into the hawthorn. It must suck in isoscelesism with its sap.
This entry has not yet been fully updated (first published 1900; most recently modified version published online December 2020).
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adj.n.1551