mandatory

US /ˈmæn.də.tɔːr.i/

UK /ˈmæn.də.tɔːr.i/

1.

required by law or rules; compulsory

:

•

Wearing a helmet is mandatory for all cyclists.

•

Attendance at the meeting is mandatory.

:

compulsory obligatory required requisite essential

:

optional voluntary discretionary