With 規則 and 規定, where do you draw the line?

Question

I've been trying to nail down the difference between 規定 and 規則. Three different dictionaries I checked define these both as some combination of "rule", "regulation", or "provision." After checking a few example sentences, I'm starting to get a feel for the differences, but I'm having trouble quantifying them.

The example sentences for 規定 all seem to refer to some sort of stronger or more official rule/ruling, such as:

小麦の輸入禁止が法律で規定された。 A wheat import ban was enacted.

医者は彼女に厳しい規定食を勧めた。 The doctor ordered her to go on a strict diet.

Whereas 規則 seems to to a less-specific rule:

君は規則を破った。 You broke the rule.

彼らは規則を知らない。 They are ignorant of the rules.

Am I on the right track? Is there a better way to think about the differences of these words? Finally, are they both even in common usage?

Answer 1

There's a huge overlap between them, but if I'm going to explain the difference...

規則 is something you may follow or otherwise violate. This is easy.

Otoh, a bit less common 規定 is just the way an organization is supposed to do its job. So, for example, when we talk about pay rules, it's 給与規程, not 給与規則.

Answer 2

I think the answer is right there in your examples.

You've used 規定 as a verb with する, but not 規則.「規則する」 isn't used. But as you've already noted, there is some overlap in meaning between 規定・規則.

It may help to think of it this way:

規定 - 「規」を定めること・定められた「規」

• deciding upon a rule ・ a rule which has been decided

規則 - 定められた「規」

• a rule which has been decided