noun

1. observance, as of laws, customs, etc.
2. 1. the act, practice, or power of noticing
   2. something noticed
3. the fact of being seen or noticed seeking to avoid observation
4. 1. the act or practice of noting and recording facts and events, as for some scientific study
   2. the data so noted and recorded
5. a comment or remark based on something observed
6. 1. the act of determining the altitude of the sun, a star, etc., in order to find a ship's position at sea
   2. the result obtained

Etymology: ME observacioun < L observatio, in LL(Ec), reverence, outward display

adjective