Emulation is when one computer system is made to act like another. In the context of video games, this refers to a computer or phone being used to play video games from other consoles, usually with older games. These games are usually obtained from websites that host them in the form of ROMs, or digital versions of the games, and the websites often don't have the rights to the games. This can lead to companies such as Nintendo pursuing legal action to prevent people from downloading their games without buying them directly.