An Etymological Dictionary of the German Language/Rast
Rast, f., ‘rest, repose,’ from MidHG. rast, raste, f., OHG. rasta, f., ‘repose, rest, permanence,’ also in OHG. and MidHG. ‘stage of a journey,’ which is the only sense borne by Goth. rasta and OIc. rǫst. Comp. AS. rœst, E. rest, OSax. rasta, ręsta, ‘couch, deathbed,’ Du. rust (see Rüste), ‘rest, repose.’ The common Teut. word is based on a root ras, ‘to remain, dwell,’ which may also be inferred from Goth. razn and OIc. rann, ‘house.’ Rast, in the sense of ‘stage,’ comes from the period when the Western Aryans were migrating to Europe; only a wandering tribe could adopt the intervals of reposing and encamping as a measure of distances. Moreover, the older language preserves a few other words as relics of the migratory period; comp. MidHG. tageweide, f., ‘day's journey, the distance traversed in a day’ (prop. said of nomadic marches, ‘the length of pasture grazed by cattle in one day’); see Hanf. Whether the assumed root ras, ‘to remain, dwell,’ is connected with the root rô in Ruhe is doubtful.