rule or law

法律(ほうりつ)	A law. $$$

規則(きそく)	A rule, like school rules, or “no smoking in the lobby.” $$$

法則(ほうそく)	A physical law, like the Law of Gravity or Murphy’s Law.

規律(きりつ)	Literally, “rule,” but closer to the English word for “discipline.” Rules typically say “don’t do this or that,” but 規律 give long lists of things you HAVE TO do, in the order you have to do them. Like if you’re at military school, you have to get up at 5:30, have your bed made by 5:35, shine your shoes by 5:40, and report to the mess hall.

掟(おきて)	The rules or codes-of-honor of secret societies:right-wing militias, yakuza, ninjas all have 法律.ZZZ