Red Light Districts

A red-light district is a part of an urban area where a concentration of prostitution and sex-oriented businesses, such as sex shops, strip clubs, and adult theaters are found. Areas in many big cities around the world have acquired an international reputation as red-light districts.

The term red-light district originates from the red lights that were used as signs of brothels.

According to the Oxford English Dictionary, the earliest known appearance of the term "red light district" in print is in an 1894 article from the Sandusky Register, a newspaper in Sandusky, Ohio. Author Paul Wellman suggests that this and other terms associated with the American Old West originated in Dodge City, Kansas, home to a well-known prostitution district during the 19th century, which included the Red Light House saloon. This has not been proven, but the Dodge City use was likely responsible for the term becoming pervasive. A widespread folk etymology claims that early railroad workers took red lanterns with them when they visited brothels so their crew could find them in the event of an emergency. However, folklorist Barbara Mikkelson regards this as unfounded.

One of the many terms used for a red-light district in Japanese is akasen (), literally meaning "red-line". (This has independent origins from the same term in English.) Japanese police drew a red line on maps to indicate the boundaries of legal red-light districts. In Japanese, the term aosen (), literally meaning "blue-line", also exists, indicating an illegal district.

...
Wikipedia