These are the top and bottom of the grapefruit. Think of these dots as the " poles " of the grapefruit, like the poles of the earth.
[header] How to prepare grapefruit for serving [title] Cut the grapefruit horizontally at its center. [step] Take a large, sharp knife and cut the grapefruit horizontally into two halves. [substeps] If you are unsure where the top and bottom of the grapefruit are, find the two dots, or navels, on the grapefruit at opposite ends.