MOBA - Multiplayer Online Battle Arena
ARTS - Action Real Time Strategy
It annoys me, greatly, that games such as League of Legends (LoL) and DOTA2 are referred to as ARTS. The term action does NOT fit with the term strategy. Strategy infers some form of logistical component to the gameplay. None of aforementioned games feature any form of logistical management. They very much focus on the action, aka tactical, gameplay elements.
MOBA, on the other hand, describes the games perfectly. They are multiplayer games that feature battles in arena-style maps. Sure, the DOTA model has lanes, creeps, and towers, but don't be fooled. DOTA is still about killing the other team. DOTA just adds objective-based gameplay into the arena (and objective-based gameplay long ago took over straight up death match).
So next time you are out at the pub talking up the latest dime-a-dozen MOBA coming down the line, please remember this post.