Fūzoku 風俗
Japanese word for the customs and manners of an era or society, also used today for the adult-entertainment industry; Itō Seiu was called a researcher of fūzoku in the older sense.
Fūzoku is an everyday Japanese word with several senses. Kotobank gives first the customs and habits of a particular time or community, as in “the fūzoku of the Meiji period.” In modern usage it also stands for the sex and adult-entertainment trade, short for fūzoku eigyō; further senses cover dress and bearing.
In the older sense, Japanese Wikipedia calls Itō Seiu a fūzoku kōshōka, a researcher of historical customs, for his work recording Edo-period life after the Great Kantō earthquake. The word also appears in magazine titles, among them Fūzoku Kitan, which the National Diet Library records as published in Tokyo by Bunken Shiryō Kankōkai until 1974.