emulator
n. C1 Advanced US //ˈɛmjəˌɫeɪtɝ// UK //ˈɛmjʊlˌeɪtɐ// em·u·la·tor
n. a piece of software that allows you to run programs or games designed for a different computer or console on your own device.
n. a software program that imitates the hardware and system software of another computer system to run applications or operating systems designed for that platform.
I use an emulator to play old games on my modern computer.
The developer used a high-fidelity emulator to test the mobile app on various Android versions before the official release.
By running a virtual emulator, researchers were able to execute the original code of a 1970s mainframe without the need for the physical hardware, preserving the software for historical study.