Precept
Etymology
From Latin "praeceptum" (a maxim, injunction), from "praecipere" (to instruct, advise beforehand), combining "prae" (before) and "capere" (to take) — literally "to take in advance." A precept is guidance taken to heart ahead of the moment it’s needed.
noun · /PREE-sept/
A general rule or maxim meant to guide conduct or thought.
What it names
A compact guiding principle — the kind of rule you carry as a saying rather than a law.
Example
"Measure twice, cut once" was the only precept his grandfather ever pressed on him.
Related idea
A precept is a rule of conduct you’re taught; a maxim is more a pithy observation about life — the first tells you what to do, the second what is so.