A rule established by authority
- A rule of conduct or procedure established by custom, agreement, or authority.
- A rule or principle of law, especially when established by precedent.
- A semi-automatic extremely low frequency (ELF) field-strength meter calibration system has been established by author.
- "This illegal trade subverts rules established by regulatory agencies to reduce the introduction of disease ..." the report said.
- I make it a rule to take a short walk after lunch.