Where did the term Kwisatz Haderach in Dune originate? I've always been curious how names and words are created in literature. Having finished the main Dune books last year, I was thinking how the term "Kwisatz Haderach" came about. Did Herbert make it up, or does it have some history or explanation to it?

Kefitzat Haderech is a Jewish phrase that means "contracting the path".

Herbert defines Kwisatz Haderach as "the Shortening of the Way" (Dune: Appendix IV), clearly meaning to reference the Hebrew here.

As seen in this answer on SFF, a large quantity of names in _Dune_ are inspired by words from Semitic languages such as Hebrew or Arabic.