Because it doesnβt seem to matter currently if you play ranked games or casual games, the general experience tends to be the same. But one has numbers and things to go with it. You still get people playing to win in casual games and you get people dicking around having fun in ranked games, and the ranks donβt necessarily indicate how they play as a team and a whole bunch of other things that make it less than ideal.
Another name for them would be adversarial multiplayer. But, basically yes. Anything where there would be winners and losers is what I would call a competitive game.
Though others narrow it down further to more high skill adversarial games like Quake and Counter-Strike and League of Legends/DOTA for their professional competitive leagues.