mandatory

(noun) the recipient of a mandate. Synonyms: mandatary.

(noun) a territory surrendered by Turkey or Germany after World War I and put under the tutelage of some other European power until they are able to stand by themselves. Synonyms: mandate.

(adj) required by rule. Synonyms: compulsory, required. Examples: "In most schools physical education is compulsory." "Attendance is mandatory." "Required reading."