18-kin 

Japanese word that, in the West, is used when referring to sexually explicit or pornographic comics and animation, usually Japanese anime, manga and computer games (see Japanese pornography, hentai). In Japan it can be used to mean "metamorphosis" or "abnormality".

18-kin, 18禁, literally 18-prohibited meaning prohibited to those that are not yet 18.

I absolutely hate the fact that everyone thinks anime is only 18-kin.

18-kin by SoHumHallelujah July 3, 2009