Synonyms for Observance (same or very similar meaning)
WordNet sense 1 (a formal event performed on a special occasion):
ceremonial, ceremony, ceremonial occasion
WordNet sense 2 (the act of noticing or paying attention):
notice, observation
WordNet sense 3 (conformity with law or custom or practice etc.):
honoring
WordNet sense 4 (the act of observing; taking a patient look):
watching
From the ODE community, based on WordNet
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