The character hen is catch-all for queerness as a peculiarity-it does not carry an explicit sexual reference. : 99 While the term has expanded in use to cover a range of publications including homosexual publications, : 107 it remains primarily a heterosexual term, as terms indicating homosexuality entered Japan as foreign words.
: 100 Japanese pornographic works are often simply tagged as 18-kin ( 18禁, '18-prohibited'), meaning 'prohibited to those not yet 18 years old', and seijin manga ( 成人漫画, 'adult manga'). Less official terms also in use include ero anime ( エロアニメ), ero manga ( エロ漫画), and the English initialism AV (for 'adult video'). Usage of the term hentai does not define a genre in Japan.