dangling pointer n. [common] A reference that doesn't actually lead
   anywhere (in C and some other languages, a pointer that doesn't actually
   point at anything valid). Usually this happens because it formerly
   pointed to something that has moved or disappeared. Used as jargon in a
   generalization of its techspeak meaning; for example, a local phone
   number for a person who has since moved to the other coast is a dangling
   pointer. Compare {dead link}.


Source: The Jargon File