I've lately heard the term Multiplayer Online Battle Arena (MOBA) used as a video game genre. The Wikipedia entry redirects to the "Defense of the Ancients" genre, hinting that this is used exclusively to describe DotA-like games (e.g. creeps, lanes, heroes, towers etc. etc.)
However, I've also seen this term used to describe games that deviate further away from DotA (in my opinion) such as Monday Night Combat or Bloodline Champions (here's one source, though I've seen other places where these games are mentioned as MOBAs).
So, what exactly does MOBA mean? What are the characteristics of MOBA games?