An Etymological Dictionary of the German Language/Annotated/Roß
Roß (1.), neuter, ‘horse, steed,’ from Middle High German and Old High German ros (genitive rosses), neuter, ‘horse,’ especially ‘charger,’ for earlier *hrossa-; compare Old Saxon hross, Dutch ros, Anglo-Saxon hors, English horse, Old Icelandic hross, neuter, ‘horse.’ Gothic *hrussa- is wanting, the term used being Old Aryan aíhwa- (Old Saxon ëhu, Anglo-Saxon eoh, Old Icelandic jór), equivalent to Latin equus, Greek ἵππος, Sanscrit áçva-s (Lithuanian aszvà, ‘mare’). In Middle High German the term Pferd appears; Roß is still used almost exclusively in Upper German with the general sense of ‘horse.’ From the Teutonic cognates is derived the Romance term, French rosse, ‘sorry horse, jade,’ The origin of Teutonic hrussa- is uncertain; as far as the meaning is concerned, it may be compared, as is usually done, with Latin currere for *curs-ere, *cṛs-ere, root kṛs, ‘to run,’ or with the Sanscrit root kûrd, ‘to leap,’ with which Old Icelandic hress, ‘quick,’ may also be connected. For another derivation see rüsten —
Roß (2.), neuter, ‘honeycomb,’ from the equivalent Middle High German râȥ, râȥe, feminine; Old High German *râȥa is by chance not recorded; corresponding to Old Low German râta, ‘favus,’ Dutch raat, feminine, ‘virgin honey’; undoubtedly a genuine Teutonic term. The derivation from Latin radius is unfounded; Old French raie de miel (from raie, ‘ray,’ radius) is due to the influence of the Teutonic word, in Gothic *rêta, feminine, which cannot, however, be traced farther back.