ob ‧ ser ‧ vance /əbˈzɜːv ə ns $ -ɜːr-/ BrE AmE noun
1 . [uncountable] when someone obeys a law or does something because it is part of a religion, custom, or ceremony
observance of
the observance of a peace agreement
the strict observance of Islam
the Memorial Day observance
2 . [countable] something you do as part of a ceremony, especially a religious ceremony:
religious observances