"pastry case with a cooked, savory filling," a specialty of the Alsace-Lorraine region, 1949, from French quiche (1810), from Alsatian German Küche, diminutive of German Kuchen "cake" (see cake (n.)). The food became fashionable 1970s; became contemptible as indicative of wimpiness 1980s.
early 12c., "a sovereign prince," from Old French duc (12c.) and directly from Latin dux (genitive ducis) "leader, commander," in Late Latin "governor of a province," from ducere "to lead," from PIE root *deuk- "to lead." It is thus related to the second element in German Herzog "duke," Old English heretoga.
Applied in English to "hereditary nobleman of the highest rank" probably first mid-14c., ousting native earl. Also used to translate various European titles (such as Russian knyaz), usually of nobles ranking below a prince, but it was a sovereign title in some small states such as Burgundy, Normandy, and Lorraine.