What is Locus Regit Actum?

Legal Definition
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.
-- Black's Law Dictionary
Legal Definition
The place governs the act.
-- Ballentine's Law Dictionary