Goulan 勾欄 [curving rails]

Also known as goulan 勾闌, goulan 構欄, youpeng 遊棚, yaopeng 腰棚, yuepeng 樂棚, etc., it refers to the commercial theatres located in the city markets of imperial China. Since courtesans and prostitutes also often did theater performance to entertain their customers, later goulan was used as a byword for brothel, while prostitute was called goulan ren 勾欄人 [people from the brothel].