'MMO' originates from the phrase 'Massively Multiplayer Online', where 'massively' refers to the large number of players, 'multiplayer' indicates multiple participants, and 'online' signifies internet connectivity.

The term 'MMO' evolved from the earlier concept of 'multiplayer online games' as internet technology advanced, allowing for larger player bases.

Initially, it referred to any online game with multiple players, but now it specifically denotes games with large-scale player interaction.