What does ‘main’ mean in gaming?
In RPGs where you can have more than one character, all at once or one at a time, most people have a “main” character who gets the most effort put into them and kicks the most ass. Thus, if in a MMORPG the group finds themselves unable to defeat some raid boss, and takes time to re-group, somebody might say “let me switch to my main”.
In Genshin Impact (and probably some other games with similar approach to team composition), a “main” character might instead be the character who is present on the battlefield most of the time, as opposed to “supports” that mostly provide assistance from off-screen, and “burst” characters who appear for a short time to great effect. Such a “main” is not always the character with the most effort put into them.
In both cases, “main” can be used as a verb, as in a phrase “I main Keqing”, meaning “my main character is Keqing”.
I haven’t seen the word “main” used much in other kinds of games, but I don’t talk about other kinds of games much. But either way, it can mean one’s preferred gameplay choice, like “sniper rifles” in a shooter or “Humans” in a strategy.