observance

noun

Etymology: From Old French observance, from Latin observantia. Equivalent of observe + -ance.

1. The practice of complying with a law, custom, command or rule.
2. The custom of celebrating a holiday or similar occasion.
3. Observation or the act of watching.
4. A rule governing a religious order, especially in the Roman Catholic church.

   “Thomas Merton was a monk in the Order of Cistertians of the Strict Observance.”

5. That which is to be observed.
6. Reverence; homage.