Meta-progression is anything outside the regular gameplay. The classic example is a roguelike. Think Hades - during a run you get new boons and powers, eventually you win (or die), and you earn some currencies that can be spent in the layer outside that gameplay to earn smaller bits of permanent progression. You can call that the meta layer or the super layer depending on how pedantic you are, but that’s the gist. MeaningfulChoices comments on What is Meta-progression in games?