Zombie

Zombies, correctly spelled zombi, were "the living dead," creatures of the undead in different cultures.

Profile
While not truly being "undead," it was possible (and often done by tribes in Haiti) to trick a human into believing they were one of the "living dead" using the drug tetrodotoxin. In correct doses, it could lower the consciousness of a person and take away their sensory nerves. The person would then be buried and dug up, making them think they had been brought back to life. They would subsequently be used as slaves. (NA: White Darkness)

Minor references
When discussing the idea of a "planet ruled by zombies", the Fourth Doctor remembered the quote that "the living are just the dead on vacation." He told Romana II that one could always identify a genuine zombie by the fact that their skin was cold to the touch, which aided him in his discovery that the Movellans were robots. (DW: Destiny of the Daleks)

Rose Tyler called the Gelth, while possessing dead human bodies, (DW: The Unquiet Dead). To Sarah Jane Smith, she described people infected with the Empty Child virus as "zombies" (DW: School Reunion, referencing DW: The Empty Child/The Doctor Dances).

Behind the scenes
David A. McIntee, when writing White Darkness, took inspiration and facts from the nonfiction book The Serpent and the Rainbow, which detailed accounts of zombification that occurred in Haiti in the early 20th century. He advised staying away from the film version.