Emulation, imitation of behavior of a computer or other electronic system with the help of another type of computer/system.

Hardware emulation is the use of special purpose hardware to emulate the behavior of a yet-to-be-built system, with greater speed than pure software emulation.

Console emulator, a program that allows a computer or modern console to emulate a video game console.

In-circuit emulation is used to emulate the processor in an embedded system, to aid in debugging.

Emulation for Logic Validation is used to emulate the hardware in a manufacturing automation environment during the design phase to aid in PLC (Programmable Logic Controller) logic debugging.

Socialist emulation, a form of competition practiced in Soviet Union

In statistics, an emulator is a special case of the Gaussian process used to estimate the output of a complex computer program without actually running it.