definition of
[mandatory]

[1] #1 mandatory s. [compulsory, required] required by rule; "in most schools physical education is compulsory"; "attendance is mandatory"; "required reading". wn

[2] #2 mandatory n. [mandatary] the recipient of a mandate. wn

[3] #3 mandatory n. [mandate] 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. wn