In Computer Science, emulation refers to the capability of a computer software or hardware to replicate the functions of another software or hardware. Hence, video game console emulators are programs that enable computers to imitate the behavior of different video game consoles such as Nintendo Entertainment System (NES), Super Nintendo Entertainment System (SNES), Game Boy (GB), Sega Dreamcast, and Sony PlayStation. To help you understand video game console emulators even more, you may check out this post: Play Classic Super Nintendo (SNES) Games on Ubuntu Linux.
-- Love zsnes.