An Etymological Dictionary of the German Language/Pfennig
Pfennig, m., ‘a coin, one-tenth of a penny,’ from MidHG. pfęnnic, pfęnninc (gen. -ges), OHG. pfęnning, m., ‘denarius, a silver coin, a twelfth of a shilling.’ Its form and origin are difficult to determine. It may be derived from Pfanne, and thus its name may be due to its shape (perhaps ‘pan-shaped’ or ‘made in the pan’). A variant with nd, from the connection of the word with Pfand, is seen in OHG. pfęnting and AS. pęnding (variants of the more usual pęnning, pęnnig, whence E. penny). With regard to the diffusion of the word, comp. further OSax. pending, Du. penning, OIc. penningr; in Goth. a presumptive form *panniggs or *pandiggs is wanting. The suffix -ing frequently occurs in names of coins in the earlier periods; comp. Schilling, Silberling, OHG. cheisuring, ‘imperial gold coin,’ E. farthing, from AS. feórþing, ‘quadrans.’ From the Teut. cognates are derived OSlov. pěnęgŭ, pěnędžĭ, ‘coin, money.’