A destructor is a special function in programming, particularly in object-oriented languages like C++ and Java. It is automatically called when an object is no longer needed, allowing the program to free up resources that the object was using, such as memory or file handles. This helps prevent memory leaks and ensures efficient resource management. Destructors typically have the same name as the class they belong to, prefixed with a tilde (~) in C++. They do not take any parameters and do not return a value. Properly implementing destructors is crucial for maintaining the stability and performance of applications, especially those that manage dynamic resources.