It's not
@Minigiant 's definition. If you Google "win state", right there at the top of the results you'll see:
What is Win-State? Definition of Win-State: A condition or state within a game or level which designates successful completion of a predetermined task or goal.
If you consider win state to be limited to "beating the game" then you're the one using it much more strictly than its accepted usage. Beating the game is a win state, but so is completing a quest, looting a dungeon successfully, or even just taking a pie from an orc.