isosceles

adj

Etymology: Borrowed from Latin īsoscelēs, from Ancient Greek ἰσοσκελής (isoskelḗs, “equal-legged”), from ἴσος (ísos, “equal”) + σκέλος (skélos, “leg”) + -ής (-ḗs, adjective suffix). See also iso-.

1. Having (at least) two sides of equal length, used especially of a triangle or trapezoid.

   “Upon each exterior side draw an Isosceles Triangle of 480 Fathoms.”

   “A right double pyramid is isosceles when the extremities of the vertex-edge are at the same distance from the plane of the base.”