precept

PRE'CEPT, n. [L. proeceptum, from proecipio, to command; proe, before, and capio, to take.]

1. In a general sense, any commandment or order intended as an authoritative rule of action; but applied particularly to commands respecting moral conduct. The ten commandments are so many precepts for the regulation of our moral conduct.

No arts are without their precepts.

2. In law, a command or mandate in writing.