MMO

abbreviation or noun

ˌem-ˌem-ˈō 

plural MMOs

: an online multiplayer game that has a persistent virtual world and that can typically support a very large number of concurrent players

The game is an MMO, or a massively multiplayer online game, that's still played by approximately 11.5 million subscribers.

—Orange County (California) Register

Battlefield V has a complex, captivating story and super fun online MMO games too.

—Sarah Kovac

PCs are also profiting from the boom in massively multiplayer online games, or MMOs, where hundreds of thousands take part in ongoing adventures over the Internet.

—Hiawatha Bray

called also massively multiplayer online game

Word History

First Known Use

2001, in the meaning defined above