(Massively Multiuser Online Game) A game on the computer played by many people. Also called "massively multiplayer online" (MMO), an MMOG differs from a regular multiplayer game because its environment is perpetual. People log in, join the action and leave whenever they wish, but the game continues like new soldiers replenishing fatigued troops on the battlefield. In 1987, the Genie online service hosted Air Warrior, an aerial combat game and the first MMOG. See MMORPG and multiplayer gaming.