The name Sovereign is a girl's name meaning "supreme ruler, ultimate power".
Sovereign is one of those names only a celebrity could introduce, much like Saint or Sir who came before it. It was actually football player Cam Newton who first used the name for his daughter, Sovereign-Dior Cambella (sister to Camidas, Cashmere, and Chosen) in 2017. But more notably, it's the name Usher chose for his baby girl, Sovereign Bo, in 2020.
You might place Sovereign in that ever-more-popular group of word names with exalted meanings: Reign. Messiah, and Bishop, to name a few. This trend is related to the trend for mythological names, from Athena to Zeus, as well as that for modern Christian names like Creed and Jericho.