The term isosceles is an adjective typically used in the field of mathematics, meaning having two equal sides. When talking about a triangle, it would mean having two sides of the triangle of identical measure. When the term isosceles is used in reference to a trapezoid, it would mean that the trapezoid has its two nonparallel sides of equal length.

An isosceles triangle is a type of triangle classified on the basis of the lengths of its sides. Such a triangle will not only have two equal sides but will also have two internal angles that are of identical degrees. These two angles will be the angles formed where both the equal sides join the third side.

The term isosceles has its roots in the Late Latin term isosceles, meaning having two equal sides; it is from the Greek term isoskeles: a break up of is- + skelos meaning leg.

An isosceles triangle is a type of triangle classified on the basis of the lengths of its sides. Such a triangle will not only have two equal sides but will also have two internal angles that are of identical degrees. These two angles will be the angles formed where both the equal sides join the third side.

The term isosceles has its roots in the Late Latin term isosceles, meaning having two equal sides; it is from the Greek term isoskeles: a break up of is- + skelos meaning leg.