Anyone who regularly watches a competitive video game stream has heard the term "meta." Many players talk about using the meta, or a character's meta, to gain an advantage or simply win.
In popular culture, meta means referencing other popular culture within itself, like art talking about art.
In video games, meta is the most effective tactic to win. More specifically, it is the best weapons, moves, characters, and playstyles. In a fighting game like Mortal Kombat 11, Jacqui's meta is pressuring opponents up close with fast buttons and relentless mixups.
That's why when games are patched, a character's meta can change. If something works well, then other players will try their best to figure out counterplay, which keeps things interesting. It only takes one person to figure out new tech for a character to evolve the meta.
The best meta, although usually not the case, is balanced. This allows for a variety of characters and unique playstyles to shine. While players want patches to make every option as viable as possible, most games heavily favor specific tactics and tools.
Active players can communicate with the developers on social media to bring any overpowered or underwhelming options to light, but it is rare for updates to directly address a majority of competitive concerns, leaving the players to improve their game's meta through labbing and the old fashioned grind.