What is Rentcharge?

Legal Definition
A rentcharge is an annual sum paid by the owner of freehold land to the owner of the rentcharge, a person who need have no other legal interest in the land. They are often known as chief rents in the north west of England but the term ground rent is used in many parts of the country to refer to either a rentcharge or a rent payable on leasehold land. This is confusing as a true ground rent is a sum payable in relation to land held under a lease. As a result, it is important to know the status of the land for which, an annual sum is paid.
-- Wikipedia