"A name given by certain primitive, superstitious peoples, particularly in certain sections of Haiti, to disinterred human corpses endowed by sorcery with power to carry out in a mechanical way the wishes of the sorcerer. It is sometimes also applied to the supernatural power or essence which these superstitious practitioners believe may enter and reanimate the dead body. An article of the Penal Code of Haiti makes the practice of Zombieism a criminal offense."
Also:
"Originally in West African voodo cults, the deity of the python; hence in Haiti and the southern U. S., the snake deity of voodo rite. The supernatural power or essence which it is believed may enter into and reanimate a dead body; also, a corpse so reanimated. A Zombi is a soulless human corpse, still dead, but taken from the grave and endowed by sorcery with a mechanical semblance of life-it is a dead body, which is made to walk and act and move as if it were alive."
Source: In a 1936 dispute over trade-marks, an American Court (Amusement Securities Corp. v. Academy Pictures Distributing Corp. ) had occasion to define the term "zombi" and we just couldn't say no to this chance to fill in our Z pages.