subgenre

noun

1. One of several categories within a particular genre.

   “You have to give director Colm McCarthy, a Scottish TV veteran making his feature film debut, and writer Mike Carey, adapting his own novel, credit for attempting the seemingly impossible task of doing something new with the zombie subgenre.”

   “Black metal is a subgenre of heavy metal music that typically takes on anti-Christian, satanic and pagan themes.”