An Etymological Dictionary of the German Language/Annotated/Becher
Becher, masculine, ‘beaker, goblet,’ from the equivalent Middle High German bëcher, Old High German bëhhar, bëhhâri, masculine; compare Old Low German bikeri, Dutch beker, Old Icelandic bikarr, whence Middle English biker, English beaker. These cognates are derived from Low Latin bicarium, allied to Latin bacar (‘vas vinarium,’ according to Festus), and still appearing in Italian bicchiere. The Latin word was naturalised in Germany perhaps as far back as the 7th century, probably at the same period as Kelch, since its c was changed into hh, ch.