 Serling, Rod (qv) (creator of the original series,  _"Twilight Zone, The" (1959)_ (qv)) made up the phrase "Fifth  Dimension" to use in one seasons opening narration. He stated that  he wanted to go one beyond the four known dimensions. A reporter one  time asked him what was the fourth dimension (given the first three  are length, width, and height). Serling supposedly answered, "I  dont know. Arent there four?"