An Etymological Dictionary of the German Language/Annotated/Reise
Reise, feminine, ‘journey, travel, voyage,’ from Middle High German reise, feminine, ‘departure, march, journey, military expedition,’ Old High German reisa, feminine, ‘departure’; allied to Old High German rîsan, Middle High German rîsen, ‘to mount, fall,’ Old Saxon rîsan, ‘to rise,’ Anglo-Saxon rîsan, English to rise, and the equivalent Gothic ur-reisan. The idea of vertical, and especially of upward motion, thus belongs every where to the root rī̆s; therefore Reise is literally ‘departure.’ Further, Middle High German and Modern High German reisen is a derivative of the substantive; compare also with the root rī̆s, English to raise and (by the change of s into r) to rear.