The term Massively Multiplayer Online (MMO) and the term is usually applied to any online video game in which a player can interact with a large number of players simultaneously.
World of Warcraft (WoW), Runescape, and EVE Online are three examples of popular MMOs in the traditional gaming industry.
Illuvium, Star Atlas, and Embersword are all examples of Blockchain MMOs. These games also fit into the RPG (Role Playing Game) genre and thus are known as MMORPGs.