Definition - What does Blue Laws mean?
Blue laws were a set of very old laws that were used to regulate standards of morality and general behavior in colonial America. These laws essentially forbade people from doing certain activities on Sundays. Some of these activities included conducting business or gambling. The term "blue laws" has stuck around and still commonly refers to any law that forbids an activity on Sundays.
Justipedia explains Blue Laws
An example of a modern day blue law is a ban on the sale of alcohol on Sundays in some places. Many of the original blue laws have been taken out of effect. The Puritans arrived in America before the United States was officially a country. So, it was not uncommon for some of their laws to revolve around religious principles, such as keeping Sunday as a sabbath, or a day of religious observation and rest. The laws of the land have changed dramatically since America became an official country, founded on separation of church and state. As a result, most of the blue laws have been changed or completely gotten rid of.