This document discusses polymorphism in object-oriented programming. Polymorphism allows the same function name to be used for different types, with the appropriate function being called based on the object type. There are two main types of polymorphism - static, which relies on function overloading and occurs at compile-time; and dynamic, which uses virtual functions and occurs at runtime. Polymorphism can be achieved through function overloading, overriding, and dynamic binding using virtual functions.