1. （对法律、习俗等的）遵守，奉行
The observance of something such as a law or custom is the practice of obeying or following it.
1. the act of observing
taking a patient look
Synonym: observationwatching
2. conformity with law or custom or practice etc.
Synonym: honoring
3. the act of noticing or paying attention
e.g. he escaped the notice of the police
Synonym: noticeobservation
4. a formal event performed on a special occasion
e.g. a ceremony commemorating Pearl Harbor