Economic relationship between a
colony and the
parent country, where the colony ships
raw materials to the parent and the parent ships back
finished goods.
This was a common practice in the 1700's and 1800's, especially in the Americas. It is very profitable for the parent country, as they are buying the raw materials at a much lower price than the finished goods are sold for; however, it tends to piss off the colonists, which leads to things like independence movements.