Locus regit actum
Black's Law Dictionary · Henry Campbell Black, M.A. · 1910
Black's Law Dictionary
In private international law. The rule that, when a legal transaction complies with the formalities required by the law' of the country where it is done, it is also valid in the country where it is to be given effect, although by the law of that country other formalities are required.
8 Sav. Syst. § 381; West. Priv. Int. Law, 159.