What is Backside?

Legal Definition
Estates. In England this term was formerly used in conveyances and even in pleadings, and is still, adhered to with reference to ancient descriptions in deeds, in continuing the transfer of the same. property. It imports a yard at the back part of, or behind a house, and belonging thereto: but although formerly used in pleadings, it is now unusual to adopt it, and the word yard is preferred. 1 Chitty's Pr. 177; 2 Ld. Raym. 1399.
-- Bouviers Law Dictionary
Legal Definition
In English law. A term formerly used in conveyances and also in pleading; it imports a yard at the back part of or behind a house, and belonging thereto.
-- Black's Law Dictionary
Legal Definition
The backyard of a house.
-- Ballentine's Law Dictionary