Ordinance

The noun ordinance is an authoritative order or regulation.

Examples:
  • No law or ordinance is mightier than understanding. (Plato)
  • Law: an ordinance of reason for the common good, made by him who has care of the community. (Thomas Aquinas)

Ordnance

The mass noun ordnance refers to military materiel (e.g., weapons, ammunition, fuel).

Examples:
  • The guns are a new and impressive addition of ordnance.
  • Military aircrafts can be used to carry a wide variety of ordnance.

A Quick Test