Desert wording

I have had a long standing debate with a considerably more erudite friend over the origins of the term desert. He argues from his extensive knowledge of linguistics and Latin that the term is derived from the verb to desert, which is predictably descended from the term de-serere, to unjoin. This is, of course, a logical and most likely correct explanation.

I, however, tenaciously hold onto an interesting anecdote related during a 9AM Egyptian Archaeology course. In ancient Egyptian (which, like its modern day cousins Hebrew and Arabic, and descendant Coptic, uses combinations of consonants to express core ideas), the term d-s-r-t described the uninhabitable 'red land' that stood in contrast to the k-m-t 'black land' of the Nile Valley.

I can find no credible explanation of how the Egyptian may have made its way into English, but it is a fun coincidence.