Ordinance - (Webster's 1828 Dictionary)
1. A rule established by authority; a permanent rule of action. An ordinance may be a law or statute of sovereign power. In this sense it is often used in the Scriptures. Exo 15. Num 10. Ezra 3. It may also signify a decree, edict or rescript, and the word has sometimes been applied to the statutes of Parliament, but these are usually called acts or laws. In the United States, it is never applied to the acts of Congress, or of a state legislature.
2. Observance commanded.
4. Established rite or ceremony. Heb 9. In this sense, baptism and the Lord's supper are denominated ordinances.