Riga
Black's Law Dictionary · Henry Campbell Black, M.A. · 1910
Black's Law Dictionary
In old European law. A species of servico and tribute rendered to their lords by agricultural tenants. Supposed by Spelman to be derived from the name of a certain portion of land, called, in England, a "rig" or "ridge," an elevated piece of ground, formed out of several furrows.
Burrill.