Short answers, pulled from the story.
The English word ghost emerges from Old English gāst, a term meaning breath, spirit, soul, or ghost. This root traces back to Proto-Germanic gaistaz and further to pre-Germanic ghois-t-oz, translating to fury or anger.
The now-prevailing sense of the soul of a deceased person appearing in visible form only emerged in Middle English during the 14th century. Before this period, the Old English word could denote any good or evil spirit such as angels and demons.
Ghosts were thought to be created at time of death taking on memory and personality. They traveled to the netherworld where they led existence similar to the living while relatives expected to make offerings of food and drink to ease conditions for these spirits.
Physician John Ferriar wrote An Essay Towards a Theory of Apparitions in 1813 arguing sightings resulted from optical illusions. He proposed that physical explanations like air pressure changes causing doors slam or humidity making boards creak account for ordinary phenomena.
Ritual feeding of the dead occurs in traditions like the Chinese Ghost Festival or Western All Souls Day. Strategies for preventing revenants may include sacrifice giving food and drink to pacify them or magical banishment.