An isosceles triangle is a type of triangle that has at least two sides of equal length. The angles opposite these equal sides are also equal, which gives the triangle its unique properties. Isosceles triangles can be found in various shapes and sizes, and they are commonly used in geometry and design. In addition to triangles, the term "isosceles" can also apply to other geometric figures, such as isosceles trapezoids, which have one pair of parallel sides and the non-parallel sides of equal length. Understanding isosceles shapes is important in fields like architecture and engineering, where symmetry and balance are essential.