the usual form of Latin dis- in Old Italian, Spanish, Portuguese, Provençal, and French. In Middle English, interchanging with dis- (which in a later period displaced it), hence such form as desarmen, desdein, deshonour, desparagen, deschargen, despisen, etc.
derring-do
derringer
Derry
*deru-
dervish
des-
Des Moines
desalination
desaturate
descant
descend