Thomas Keightley was an Irish writer known for his works on mythology and folklore, particularly Fairy Mythology. A fairy is the name given to an alleged metaphysical spirit or supernatural being. The fairy is based on the fae of medieval Western European folklore and romance. Fairies are often identified with related beings of other mythologies. Even in folklore that uses the term "fairy," there are many definitions of what constitutes a fairy. Sometimes the term is used to describe any magical creature, including goblins or gnomes: at other times, the term only describes a specific type of more ethereal creature.