What is Ground Annual?

Legal Definition
In Scotch law. An annual rent of two kinds: First, the feu duties payable to the lords of erection and their successors ; second, the rents reserved for building lots in a city, where sub-feus are prohibited. This rent is in the nature of a perpetual annuity. Bell; Ersk. Inst 11, 3, 52,
-- Black's Law Dictionary
Legal Definition
(Scotch) An annual rent.
-- Ballentine's Law Dictionary