The quality of being better than all others.
Supereminence is a very good thing, like being the best at something.
Examples:
Her supereminence in math made her the top student.
The supereminence of the team was clear in their victory.
The supereminence of the cake made it the best in the contest.
The supereminence of the superhero made all the other heroes jealous.
The supereminence of the mountain made it the tallest in the world.
The supereminence of the sun makes it the biggest thing in the sky.