A cubic spline is a mathematical tool used for interpolation, which means it helps create smooth curves through a set of points. It consists of piecewise cubic polynomials that connect these points, ensuring that the curve is continuous and has continuous first and second derivatives. This smoothness makes cubic splines ideal for applications in computer graphics, data fitting, and numerical analysis. In practice, cubic splines are often used in scenarios where a simple linear interpolation would not provide a satisfactory result. For example, in computer-aided design or data visualization, cubic splines can create visually appealing curves that accurately represent the underlying data trends without sharp corners or abrupt changes.