ROMs, short for Read-Only Memory, are digital copies of games that are extracted from the original game cartridges or discs. They contain the game's data, including its code, graphics, and soundtracks. ROMs can be played on a computer or other devices using emulators, which mimic the behavior of the original console. While ROMs can be obtained through various means, including ripping from personal game collections, downloading from online sources is a common practice.