isosceles, a. (n.) Geom.
(aɪˈsɒsɪliːz)
Also 6–7 isoscheles.
[a. late L. īsoscelēs, a. Gr. ἰσοσκελής equal-legged, f. ἰσο- + σκέλος, σκελε- leg.]
Of a triangle: Having two of its sides equal. (Formerly sometimes as n.: An isosceles triangle.)
| 1551 Recorde Pathw. 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. 1570 Billingsley Euclid i. Def. xxv. 5 Isosceles, is a triangle, which hath onely two sides equall. 1571 Digges Pantom. i. B iij a, Isoscheles is such a Triangle as hath onely two sides like, the thirde being vnequall, and that is the Base. 1656 Stanley Hist. Philos. v. (1701) 186/2 The Element of a Cube is an Isosceles Triangle, for four such Triangles concurring make a Square, and six Squares a Cube. 1674 N. Fairfax Bulk & Selv. 115 We are born in hand with this, That then a Scalenum and Isosceles would be all one. 1798 Canning, etc. Loves Triangles in Anti-Jacobin 7 May, 'Twas thine alone, O youth of giant frame, Isosceles! that rebel heart to tame. 1802 Bournon in Phil. Trans. XCII. 307 With isosceles triangular planes. 1812–16 Playfair Nat. Phil. (1819) I. 87 The resistance to the motion of an isosceles wedge. |
Hence iˈsoscelesism (better iˈsoscelism) nonce-wd., the character of being isosceles.
| 1851 Ruskin Stones Ven. I. xxi. §32 But the spirit of the triangle must be put into the hawthorn. It must suck in isoscelesism with its sap. |