An Etymological Dictionary of the German Language/Annotated/Treber
Treber, plural, ‘husks, grains,’ from the equivalent Middle High German tręber, Old High German trębir, plural; the corresponding singular would be trab. Compare Icelandic draf, Dutch draf, ‘sediment of a brewing’ (to which drabbe, ‘lees,’ is allied), Anglo-Saxon drœf, English draff, ‘lees, refuse, dregs’ (late Anglo-Saxon drabbe, ‘lees, dregs, dirt,’ whence English drab, applied to colour and a woman). If the medial ƀ of the Teutonic base draboz, neuter, could have originated in a guttural, the word might be compared with Old Icelandic dregg (equivalent to English dregs), and hence be probably allied to Latin frăces, ‘grounds, dregs of oil’; Aryan root dhraq?. It seems to be also connected more remotely with Trester, ‘husks, skins (of grapes).’