isosceles

1. (geometry) Having (at least) two sides of equal length, used especially of a triangle or trapezoid.Examples: "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."; "To prepare for the application of his method, Saccheri made use of a figure with which we are already acquainted. This is the isosceles quadrilateral with the two base angles right angles."not-comparable