Game Discs are the storage medium for Nintendo GameCube, Wii and Wii U. They are digital optical discs usually containing games and are used for the physical retail releases. While Wii and Wii U discs are of a regular size, the Nintendo GameCube discs are much smaller.
The Game Disc is placed inside the console's lid (Nintendo GameCube) or disc drive (Wii/Wii U) to play the game after it is powered on. For the Wii and Wii U the player must confirm the game on the Home Menu, and involves the Disc Channel for Wii.