mandatory in WordNet English dictionary

1. required by rule
   "in most schools physical education is compulsory"; "attendance is mandatory"; "required reading"
   compulsory  mandatory  required 
   

1. the recipient of a mandate
   mandatary  mandatory 
   
2. 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
   mandate  mandatory