An Etymological Dictionary of the German Language/rot
rot, adj., ‘red,’ from the equiv. MidHG. and OHG. rôt, adj.; corresponding to the equiv. Goth. rauþs, OIc. rauðr, AS. reád, E. red (AS. also reód, OIc. rjóðr, ‘red’), Du. rood, OSax. rôd. Goth. and common Teut. rauda-, from pre-Teut. roudho-, is a graded form of the widely-diffused Aryan root rū̆dh, ‘to be red,’ which appears also in ModHG. Rost (2), as well as in OHG. rutichôn, ‘to be reddish,’ MidHG. rō̆ten, ‘to redden,’ and MidHG. rŏt, ‘red’; also in Goth. gariudjô, ‘shamefacedness,’ and perhaps Goth. *bi-rusnjan, ‘to honour,’ AS. rudu, ‘redness,’ and rûd, ‘red,’ E. rud (AS. rudduc, E. ruddock). In the non-Teut. languages, besides the words adduced under Rost (2), the following are the principal cognates: Sans. rudhirá-s, ‘red,’ rôhita, ‘red’ (for *rôdhita); Gr. ἐρυθρός, ‘red,’ ἔρευθος, ‘redness, flush,’ ἐρυσίπελας, ‘erysipelas,’ ἐρεύθω, ‘to redden’ (OIc. rjóða; AS. reódan, ‘to redden, kill’); Lat. ruber (rubro- for *rudhro-, Gr. ἐρυθρός, like barba for *bardhâ, see Bart), rufus, ‘red,’ rubidus, ‘dark red,’ rubeo, ‘to blush with shame’; OSlov. rŭdrŭ, ‘red,’ rŭděti sę, ‘to blush’; Lith. rùdas, rùsvas, ‘reddish brown,’ raúdas, raudónas, ‘red,’ raudà, ‘red colour.’ It is noteworthy that red in several of these languages is a sign of shame. Moreover, the Teut. cognates may be explained from an Aryan root rut, which appears also in Lat. rŭt-ilus, ‘reddish.’ — Derivatives Rötel, m., ‘red chalk,’ from MidHG. rœtel, rœtelstein, m., E. ruddle; comp. the equiv. Lat. rubrĭca, from ruber. — Röteln, plur., ‘measles.’ —