Unitas Actus Law and Legal Definition

Unitas actus is a Latin term which means unity of action or a single act. It is used in the execution of a will. In execution of a will it is presumed that the execution must not be interrupted by any intervening act.

In In re Roe's Will, 82 Misc. 565, 571 (N.Y. Misc. 1913), the court held that, by the Roman law the signing and sealing of the testament by the testator, or in his/her presence, and the due publication of the will must take place on one occasion, unitas actus, before the testator and the assembled witnesses, who must then subsign and subseal the same before the session could be interrupted by extraneous matter.