Friedrich Kluge, An Etymological Dictionary of the German Language (1891)
“ Keule is a ‘pole with a ball-shaped end.’ Kugel and Kegel cannot possibly be related by gradation. Kuh, feminine, ‘cow,’ from the equivalent Middle High German and Old High German kuo, feminine; compare Middle Low German kô, Dutch koe, English cow, Anglo-Saxon cû, Old Icelandic kýr, feminine (Gothic *kôs) ; Teutonic type kô-, feminine, ‘cow.’ This word, like the names of other domestic animals, is found in the non-Teutonic languages, and in the form of gō̆w (gô) it is common to the Aryan group; compare Indian gâus (accusative gâm) , feminine, Greek βούς (stem βοϝ) , Latin bos (stem bov-) . ”
