家规 are the rules of conduct passed down within a family, traditionally formalized in
家训 (family precepts) — written codes by Confucian scholars like
颜氏家训 (Yan Family Precepts). In modern usage, often refers to informal household rules. Pair with
国法 in the proverb
国有国法,
家有家规 ('the state has its laws, the family has its rules').