Haha! or Fossee, are Terms of the same Signification, tho' the First is a new coin'd Word, they mean a Ditch, or Moat to Enclose a Garden, whether the Ditch has Water in it, or not, but the Haha, by the Custom of five or six Years, intimates a dry Ditch, so regulated by Slopes, and so Deep that it is unpassable. It makes a fine open Fence to a Ground.
1731, Richard Bradley, New improvements of planting and gardening, both philosophical and practical, London, page 164