Many terms are also straight from ancient history:
In early Dungeons and Dragons, you would roll the dice to determine your character's stats.
Items or abilities that have a fixed chance of activating an additional effect are termed proc. The term is from some of the first Multi-User Dungeons, text based online RPGs, which called them spec_proc for Special Procedure.
I generally don't care what terms people have for these things, but the ones I tend to use are Character, Tank, Tell, and Raise. I often differentiate DPS between melee, ranged, and casters. I have never heard of 'mez,' and the effect to which Archellion proscribes it is what I've always known as sleep. I've always used whatever term the game uses to describe a game-supported association of players - Free Companies in FFXIV. Patrols may also be pats, and threat and hate are interchangeable; aggro is only something that happens when a monster begins attacking a new target.
Specifically in this game, I've taken to calling stuns interrupts instead, as that's all they seem to be good for.