[acheron]

it's only a graveyard if it's next to a church.

Not true. You can have cemeteries with a church or graveyards not. There's a connotation of "graveyards" as older than cemeteries, and most older ones were near churches, but it's never been a strict definition.

While we're on it though, "graveyard" is a recentish word ("grave" and "yard" are both old Germanic words but the compound word only comes from the 1700s). The Old English word was "licburg", meaning "corpse town". ("lic" is the source of the D&D/fantasy game "lich")