In 18th century Scotland, bo, boo, and bu would latch onto plenty of words describing things that went bump in the night. Serious scientists were sending electrical shocks through the bodies of corpses to see if reanimating the dead was possible; readers were engrossed in terrifying Gothic fiction (think Frankenstein, Zastrozzi, and The Vampyre); British police departments were reporting a heightened number of ghost sightings as graveyards were plagued by “ghost impersonators,” hoaxsters who camped out in cemeteries covered in white robes and pale chalk. Now that you know why ghosts say “boo,” find out a few regional terms for spirits and haunts that you might want to work into conversation, and learn about “ghost words”—nonexistent words that somehow found their way into the dictionary.