Blue Law

A blue law is a type of law designed to enforce religious standards, particularly the observance of a day of worship or rest. In the US, most blue laws have been repealed, declared unconstitutional, or are simply unenforced; though prohibitions on the sale of alcoholic beverages or prohibitions of almost all commerce on Sundays are still enforced in many areas. Blue laws often prohibit an activity only during certain hours and there are usually exceptions to the prohibition of commerce, like grocery and drug stores. In some places, blue laws may be enforced due to religious principles, but others are retained as a matter of tradition or out of convenience.

Many European countries, such as Germany, ban most Sunday shopping. In Saudi Arabia, eating in public during the daytime is prohibited during the holy month of Ramadan.