noun
licensed red-light district
Historical term for officially designated pleasure quarters, especially in the Edo period. Refers to areas where prostitution and entertainment were legally permitted under government license.
江戸時代、吉原は有名な三業地だった。
In the Edo period, Yoshiwara was a famous licensed red-light district.
From 三業 (さんぎょう, 'three businesses') + 地 (ち, 'district'), referring to the three licensed trades: restaurants, geisha houses, and brothels.