국룰
gungnul
The unwritten rule everyone follows.
OriginShort for 국민 룰 (the nation's rule).
When to useRamyeon after swimming, chicken during the World Cup — things that “must” go together.
CarefulCasual — fine with friends, out of place in formal writing or with your boss.
Examples
비 오는 날엔 파전이 국룰이지.
Pancakes on a rainy day — that's the rule.