A beautiful black girl or woman with a brown and dark skintone. A black woman will melanin. A cute nickname for describing a black woman that the man (non black men)is into. Similar to black queens.
Look at this girl over there! She a beauty , nice brown sugar.
circa 2002 - When a black man and woman have been friends since their childhood or a long period of time, and have built up an attraction to each other but hides it, before it finally comes out.
"Brian and Christina are brown sugar - I don't know why they frontin'."