In Japanese, BL is the most common term for gay fiction in general. If it's gay porn, it's yaoi, if it's lesbian porn, it's yuri, and if it's not porn, it's called shounen-ai and shoujo-ai for gay and lesbian romance, respectively. In English, yaoi is the most common term for explicit gay fiction.
The term yaoi refers mainly to explicit gay fiction, but the way it's used in English and in Japanese differs. Left: Usui Kenta 雨水健太 Right: Maaka Ren 真紅煉 Anime: Karin かりん (Episode 12, Censored)
