What is "massively multiplayer online game"

n. (context online gaming English) A computer game in which a large number of players can simultaneously interact in a persistent world.

A massively multiplayer online game (MMOG or MMO) is an online game which is capable of supporting large numbers of players simultaneously in the same instance (or world). MMOs usually feature a huge, persistent open world, although some games differ. These games can be found for most network-capable platforms, including the personal computer, video game console, or smartphones and other mobile devices.

MMOs can enable players to cooperate and compete with each other on a large scale, and sometimes to interact meaningfully with people around the world. They include a variety of gameplay types, representing many video game genres.