Original: According to the fictional universe first established by Slayer, the 'Buffyverse,'The term 'Buffyverse' is used amongst fans of Buffy/Angel online to describe the fictional universe established by Buffy/Angel.
Simplified: In the fictional universe created by Buffy (the Buffyverse),The term 'Buffyverse' is used amongst fans of Buffy/Angel online to describe the fictional universe established by Buffy/Angel.