An Etymological Dictionary of the German Language/weiß
weiß, adj., ‘white, blank,’ from the equiv. MidHG. and OHG. wîȥ (from hwîȥ), adj.; corresponding to Goth. hweits, OIc. hvítr, AS. and OSax. hwít, Du. wit, E. white. This common Teut. term (hwîto-) is based on an Aryan root kwī̆d, kwī̆t, from which are derived Sans. çvit, ‘to be white, to shine’ (so too çvêtá, çvitrá, çvitna, ‘white’), Zend spaẹta, ‘white,’ OSlov. světŭ, ‘light,’ and Lith. szvaitýti, ‘to make bright.’ Goth. hwaiteis (ModHG. Weizen, ‘wheat’), is related by gradation.