An Etymological Dictionary of the German Language/Annotated/Pfau
Pfau, masculine, from the equivalent Middle High German pfâwe, Old High German pfâwo, masculine, ‘peacock’; the Old High German form, with its permutated initial sound and its preservation of the v as w (see Käfig, Pferd), points to a very early loan-word from Latin pâvo (whence also French paon, Italian pavone). With regard to the form of the word, it may be remarked that while other loan-words from Latin are based on the oblique case (see Kreuz), in this instance the German word is classified under the n- declension, to which Latin pâvo (accusative pâvôn-em) also belongs. The peacock (compare mausern and Käfig) may have been known in Germany about the 7th or 6th century, or even earlier. Compare Dutch paauw, Anglo-Saxon pâwa and peá, English peacock, which were borrowed contemporaneously from the same source; Old Slovenian pavŭ is also allied.