Cemetery vs. Graveyard

Cemetery is the much older word, going back to Roman times. Today, a cemetery refers to a large burial ground, typically not associated with a church.
The first citation in the Oxford English Dictionary for graveyard comes from 1767, and **a graveyard is typically smaller than a cemetery and is often associated with a church.** It is part of the churchyard.
Cemetery appears to be the more commonly used word today, perhaps because it’s been around longer, perhaps because people like the sound of it better, or perhaps because there are so many more people buried in cemeteries because they’re so much bigger than graveyards. It was actually the population growth in Europe that led to the creation of large cemeteries because the small churchyards could no longer hold all the dead, so I’m inclined to think their popularity as a resting place is also the reason the word it more popular.