In classic cuisine, “supreme” is used to describe the best cut of anything.
This cut is used to incorporate citrus into recipes without adding the rind or pith. Slice the top and bottom off the citrus fruit so it stands up straight, and doesn’t roll. With a sharp knife, slice from the top of the fruit to the bottom, removing the rind and the pith all the way around the fruit. The brightly colored inner fruit should be exposed. Remove every bit of clinging pith that you can. (Bits of pith are the sign of an amateur supreme.)
Now, hold the fruit in your hand and slice to the center on each side of each membrane that divides each section. As you do this, the supremes should fall out. (They look like naked sections). I find that a serrated knife works best for this job. I also like to do it over a bowl so I don’t lose any juice. When all the sections are removed, squeeze out the membrane and chuck it.