A Megaverse is a group collection many Multiverses, some Membraneverses, and Kiloverses, Hyperverse is in the center. It is different from a Metaverse because a Megaverse is physical. Our megaverse is infinity.
So it is an 16+2 dimensional self-containing infinite set of an infinte amount of simulatneously existing multiverses that represent an infinite amount of outcomes and inter-universal laws for every one,including the one we live in. It's size can be up to 10 to the power of 100 to the power of 1000 light-years.