One of the many terms used for a red-light district in Japanese is akasen (赤線?), 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 (青線?), literally meaning "blue-line," indicates a non-legal district, also exists.

In the United States during the 19th and early 20th centuries, the term sporting district became popular for legal red-light districts. Municipal governments typically defined such districts explicitly to contain and regulate prostitution.

A red-light district is a neighborhood or a part of a neighborhood where businesses connected to the sex industry (sex shops, strip clubs, adult theaters etc.) exist. In some red light districts, prostitution may legally take place; other red light districts are known for their illegal prostitution scene. The term "red-light district" was first recorded in the United States in 1894, in a newspaper article in The Milwaukee Sentinel of Wisconsin.[citation needed] Other mentions from the 1890s are numerous, from locations all over the United States. Possibly the best known red-light district is De Wallen in Amsterdam, Netherlands.

One of the many terms used for a red-light district in Japanese is akasen (赤線?), 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 (青線?), literally meaning "blue-line," indicates a non-legal district, also exists.

In the United States during the 19th and early 20th centuries, the term sporting district became popular for legal red-light districts. Municipal governments typically defined such districts explicitly to contain and regulate prostitution.