- /maendat(a)riy/ adj. Containing a command; preceptive; imperative; peremptory; obligatorySee also mandatory injunction@ mandatory instructions@- mandatory presumption (presumption)@ mandatory sentencingSee sentence@ mandatory statutesGeneric term describing statutes which require and not merely permit a course of action. They are characterized by such directives as "shall" and not "may." A "mandatory" provision in a statute is one the omission to follow which renders the proceedings to which it relates void, while a "directory" provision is one the observance of which is not necessary to validity of the proceeding. It is also said that when the provision of a statute is the essence of the thing required to be done, it is mandatory, Kavanaugh v. Fash, C.C.A.Okl., 74 F.2d 435, 437;otherwise, when it relates to form and manner, and where an act is incident, or after jurisdiction acquired, it is directory merely. Mandatory statutory provision is one which must be observed, as distinguished from "directory" provision, which leaves it optional with department or officer to which addressed to obey it or not. State ex rel. Dworken v. Court of Common Pleas of Cuyahoga County, 131 Ohio St. 23, 1 N.E.2d 138, 139, 5 O.O. 291@
Black's law dictionary. HENRY CAMPBELL BLACK, M. A.. 1990.