The Archverse is a very large and unthinkable plane in the Omniverse. It contains the Hendaverse and is contained by the Voidverse. It is also called a Dokaverse. The Voidverse, Tradakaverse, or the 2nd Archverse is the verse that the Archverse is contained in. It is a universe of the highest rank.
Why it is the highest rank universe
The Archverse is not a universe itself, but it contains so many verses, that is why it is a regular verse in the highest rank. Arch- is a prefix meaning "the highest", so that's why it is called an Archverse.