Originally: barley, Hordeum vulgare. In later use specifically: six-rowed barley, a high-protein variety having six longitudinal rows of fertile spikelets in each spike, now chiefly used in the production of alcoholic beverages.
knocked bere, ring bere, rough bere, Scotch bere, ware bere: see the first element.
Old English; earliest use found in Bede's Ecclesiastical History. Cognate with (in different stem classes) North Frisian (Föhr, Amrum) bere, (Mainland) bär, ber, Old Icelandic barr, Gothic *baris from the same Indo-European base as classical Latin farr-, far spelt, grain, (with suffixation) Old Church Slavonic brašĭno food, Old Russian borošĭno (farinaceous) food, and more remotely Early Irish bairgen, Welsh bara, both in the sense ‘bread’; further etymology uncertain and disputed, perhaps from an Indo-European base meaning ‘point, spike, bristle’ reflected in barse, birse, bristle, etc. (the grain being so called on account of its shape), or perhaps a loanword from a non-Indo-European substrate language.