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.
It's from the Hebrew phrase "Kefitzat Haderech", which literally means "contracting the path".
This is even more likely considering "Kwisatz Haderach" means "Shortening of the Way" in Chakosba, a language in Dune.