Precept, n.
Etymology: [L. praeceptum, from praecipere to take beforehand, to instruct, teach; prae before + capere to take: cf. F. précepte. See Pre-, and Capacious.]
1. Any commandment, instruction, or order intended as an authoritative rule of action; esp., a command respecting moral conduct; an injunction; a rule. For precept must be upon precept. Isa. xxviii. 10. No arts are without their precepts. Dryden.
2. (Law)
A command in writing; a species of writ or process. Burrill.
Syn. -- Commandment; injunction; mandate; law; rule; direction; principle; maxim. See Doctrine.
1 other Webster entry under this spelling
Precept, v. t.
To teach by precepts. [Obs.] Bacon.
Shades of meaning
Fernald has no entry of its own for precept; he lists it under doctrine, proverb.
Where he writes about it:
A precept relates not to belief, but to conduct. — from doctrine
Precept is a command to duty; motto or maxim is a brief statement of cherished truth, the maxim being more uniformly and directly practical; "God is love" may be a motto, "Fear God and fear naught," a maxim. — from proverb