An Etymological Dictionary of the German Language/Pfau
Pfau, m., from the equiv. MidHG. pfâwe, OHG. pfâwo, m., ‘peacock’; the OHG. 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 Lat. pâvo (whence also Fr. paon, Ital. pavone). With regard to the form of the word, it may be remarked that while other loan-words from Lat. are based on the oblique case (see Kreuz), in this instance the G. word is classified under the n- declension, to which Lat. pâvo (acc. pâvôn-em) also belongs. The peacock (comp. mausern and Käfig) may have been known in Germany about the 7th or 6th cent., or even earlier. Comp. Du. paauw, AS. pâwa and peá, E. peacock, which were borrowed contemporaneously from the same source; OSlov. pavŭ is also allied.