obligatory

1 ENTRIES FOUND:
obligatory /əˈblɪgəˌtori/ Brit /əˈblɪgətri/ adjective
obligatory
/əˈblɪgəˌtori/ Brit /əˈblɪgətri/
adjective
Britannica Dictionary definition of OBLIGATORY
1 
formal : required by a law or rule
2 
always used before a noun, humorous : always or often included as a familiar and expected part of something