Emulation: Reproduction of a different computer, software system, or other electronic's actions and functions. Not to be confused with simulation.
High-Level Emulation (HLE): A form of emulation in which the internal code of a device is abstracted, rewriting said code into another programming language, often a variation of C, hooking the abstracted code into a console function and running that version of the code instead. Not to be confused with Low-Level Emulation (LLE).