1. The act or practice of observing or complying with a law, custom, command, or rule.
2. The act or custom of keeping or celebrating a holiday or other ritual occasion.
3. A customary rite or ceremony.
4. The act of watching; observation: "Consider how much intellect was needed in the architect, and how much observance of nature" (John Ruskin).
5. Roman Catholic Church. The rule governing a religious order.

The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved.