Copy elision is an optimization technique used by compilers to eliminate unnecessary copying of objects in programming languages like C++. When an object is returned from a function, instead of creating a copy, the compiler can directly construct the object in the location where it will be used. This improves performance by reducing overhead. This optimization is often applied in scenarios involving temporary objects, such as when returning a local object from a function. By avoiding the copy, copy elision can lead to more efficient code execution while maintaining the same observable behavior for the programmer.