Why is dereferencing a pointer called dereferencing?
A pointer refers to an object. Ergo, we dereference the pointer (or, get the referent of the pointer) to get the object pointed-to.
The de- prefix most likely comes from the Latin preposition meaning from; I suppose you could think of dereference as meaning "to obtain the referent (or object) from the reference."
Dereferencing means taking away the reference and giving you what it was actually referring to.
A pointer to something really means that your pointer variable holds a memory address of something. But the pointer can also be thought of as a reference to something instead.
Wiktionary only contains definitions related to programming: http://en.wiktionary.org/wiki/dereference
So it looks like it's really just technical jargon.