Hentai is defined differently in English. Usage of the term hentai does not define a genre in Japan. 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'). : 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'). : 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. The character hen is catch-all for queerness as a peculiarity-it does not carry an explicit sexual reference.
In sexual contexts, it carries additional meanings of ' perversion' or 'abnormality', especially when used as an adjective : 99 in these uses, it is the shortened form of the phrase hentai seiyoku ( 変態性欲) which means 'sexual perversion'. Hentai is a kanji compound of 変 ( hen 'change' or 'weird') and 態 ( tai 'appearance' or 'condition'), and means 'metamorphosis' or 'transformation'.