Final fantasy XI online is their first implement of tanks in the forms of “Blood tanks” and “Bleed tanks” which are the terms made up to describe how the company allowed players to tank differently with different classes, blood tanks being the main tank/paladin like tank and blink being the off tank form of tank (the brawler).
A lot of companies didnt directly say “you see this guys, this is named a tank”, but the term of tanking was not originated in gaming, it was implemented to describe characters/builds/classes that can soak damage or relieve pressure through forms of aggro, high sustain and (usually) slow and high damage, as well as close range domination generally.
Its why brawlers in mmorpgs are so tanky. They arent necessarily tanks, they often dont have means of taking aggro, but they have high sustain and high damage, just usually they are slower, easier to kite and dodge due them being close range and very heavy / buildup abilities, but they are such a threat at a close range that u have to respect it.
Think of the classic mmo brawler that used a broadsword or some of giant sword and does a long charge up large swing and smashes it on the ground in a small radius of damage, very classic move, very characteristic of tank.
Basically tanks exist very much before even the name of tanks being mentioned, playerbases have long since established their uses. Even in Pokemon, a game that literally has zero classes or names, is characteristic of tank usage (when ubers not allowed) in competitive, such as back in gen 4 competitive there was a common Blissey Baton Pass strat, and why Rain Team was so common and convenient because Water types had highest average HP in the game, while having high special attack (with rain dance further increasing dmg) + the mix of rain and abilities usually doubling the speed of a pokemon or healing them (Swift Swim in example).
Like I said, forms of tanks existed since almost always, Im not sure why people in Overwatch are so unfamiliar of it, I assume because most come from games like CoD which is rather braindead. Only in OW I see people trying to excuse why a tank shouldnt tank and its fps, despite ow being far more towards a MOBA and objective based than it is towards the fps games like Val and CoD. OW is almost a spit image of paladins in it’s concept, and paladins is by far more of a moba than it is an fps.
Oh and FYI, I dont support tanks being too tanky as a tank main, the mix of brawl and meatshield is good and why tanks like Monke are perfect IMO (not too offensive or too defensive, a perfect usage of mobility to cover for other lacks), but people here act as if Tank is anything new to the gaming world.