Causa rei
Black's Law Dictionary · Henry Campbell Black, M.A. · 1910
Black's Law Dictionary
In the civil law. The accessione, appurtenances, or fruits of a thing; comprehending ali that the claimant of a principal thing can demand from a defendant in addition thereto, and especially what he would have had, if the thing had not been withheld from him, Inst. 4, 17, 3; Mackeld.
Rom. Law, § 166.