fet, 同foot, 脚。即跑腿。
A peculiarly weird type of apparition is the wraith (q.v.) or double, of which the Irish fetch is a variant. The wraith is an exact facsimile of a living person, who may himself see it. Goethe, Shelley, and other famous men are said to have seen their own wraiths. The fetch makes its appearance shortly before the death of the person it represents, either to himself or his friends, or both. [Lewis Spence, "An Encyclopedia of Occultism," 1920]