Mandatory

n. [Lat. mandatarĭus, from mandatum, a charge, commission, order, from mandare, to commit to one's charge, to commission, to order; Fr. mandataire, Sp. & It. mandatario.]

1. One to whom a command or charge is given; hence, specifically, a person to whom the pope has, by his prerogative, given a mandate or order for his benefice. Ayliffe.
2. (Law.) One who undertakes, without a recompense, to do some act for another in respect to a thing bailed to him. Kent.