A ghost is the spirit of a dead person, believed by some to appear to the living. Stories of ghosts appear in nearly every culture: the ancient Romans feared lemures, restless spirits who haunted their former homes, while Japanese folklore tells of yurei, ghosts who linger because of strong emotions or unfinished business.

In fiction, ghosts might rattle chains, walk through walls, or appear as mysterious figures in old houses. Charles Dickens' “A Christmas Carol” features three ghosts who visit the miserly Ebenezer Scrooge on Christmas Eve, helping him become a better person. Shakespeare's “Hamlet” begins with guards encountering the ghost of Hamlet's dead father. These stories use ghosts to explore memory, guilt, and what we leave behind when we die.

The word also means to disappear suddenly or ignore someone completely. If someone ghosted you after promising to help with a group project, they vanished without explanation. A ghost town is a place once bustling with people but now abandoned, with empty buildings standing like memories of busier times.