A role-playing game, often abbreviated to RPG, is a type of game in which the player takes the role of one or more characters in the game's setting.
Role-playing video game
A role-playing video game is a game made for a specific platform (computer, playstation), usually by a certain company. This may be online, such as in the case of an MMORPG, but can be offline as well.
Textual role-playing game
A textual role-playing game is when the game's players write or type out the actions, words and thoughts of their characters. Textual role-playing is also called simming and can be done through many means, such as on forums (play-by-post), through e-mail (play-by-email) or on a wiki (play-by-wiki).