As lot of other semantic discussions, may be "Tank" is not the name I'd have given to them, but the important thing is everyone knows what are you saying so...tank is it. I mean, why complicating yourself giving something a name only you will use and understand? To reafirm your individuality or something? I think is better call it like everyone else does even if you don't like it, is less confusing and more pragmatic.
Imagine you are in a lobby, "Front line warrior looking for raid"...3 hours later you are still shouting "Front line warrior looking for raid". Congratulations, you reafirmed your individuality and wastd 3 hours XDDDD