Seinen
Seinen (青年) is a genre of anime or manga that is generally targeted at a 18 - 25 year old male audience (josei being the female equivalent). Sometimes it is classified as shoujo (technically incorrect) or shonen, but it has distinct features, usually classified by a wider variety of art styles (particularly in manga) and more variation in subject matter, ranging from the avant garde to the pornographic.
A common way to tell if a comic is seinen is by looking at the title of the magazine it was published in. Usually Japanese manga magazines with the word young in the title (Young Jump for instance) are seinen. Other popular seinen manga include Afternoon and Big Comic. Many of these manga were published in English in the now defunct pulp magazine.
List of seinen anime and manga