An emulator is a software or hardware tool that allows one computer system to mimic the functions of another. This enables users to run applications or games designed for a different platform, such as playing classic video games from older consoles on a modern PC. Emulators recreate the original system's environment, making it possible to experience software that may no longer be available. Emulators are commonly used for various purposes, including software development, testing, and gaming. They can help developers ensure their applications work across different systems. Additionally, emulators provide a way for enthusiasts to enjoy retro gaming experiences without needing the original hardware.