observance

1 ENTRIES FOUND:
observance /əbˈzɚvəns/ noun
plural observances
observance
/əbˈzɚvəns/
noun
plural observances
Britannica Dictionary definition of OBSERVANCE
1 
[noncount] : the practice of following a custom, rule, law, etc. — often + of
2 
[count] : an act that is part of a ceremony or ritual — usually plural