What does Boxing Day have to do with boxing?
Old English pening, penig, Northumbrian penning "penny," from Proto-Germanic *panninggaz (cf. Old Norse penningr, Swedish pänning, Danish penge, Old Frisian panning, Old Saxon pending, Middle Dutch pennic, Dutch penning, Old High German pfenning, German Pfennig, not recorded in Gothic, where skatts is used instead), of unknown origin.
Offa's reformed coinage on light, broad flans is likely to have begun c.760-5 in London, with an awareness of developments in Francia and East Anglia. ... The broad flan penny established by Offa remained the principal denomination, with only minor changes, until the fourteenth century. [Anna Gannon, "The Iconography of Early Anglo-Saxon Coinage," Oxford, 2003]The English coin was originally set at one-twelfth of a shilling and was of silver, later copper, then bronze. There are two plural forms: pennies of individual coins, pence collectively. In translations it rendered various foreign coins of small denomination, especially Latin denarius, whence comes its abbreviation d.
(Gr. denarion), a silver coin of the value of about 7 1/2d. or 8d. of our present money. It is thus rendered in the New Testament, and is more frequently mentioned than any other coin (Matt. 18:28; 20:2, 9, 13; Mark 6:37; 14:5, etc.). It was the daily pay of a Roman soldier in the time of Christ. In the reign of Edward III. an English penny was a labourer's day's wages. This was the "tribute money" with reference to which our Lord said, "Whose image and superscription is this?" When they answered, "Caesar's," he replied, "Render therefore to Caesar the things that are Caesar's; and to God the things that are God's" (Matt. 22:19; Mark 12:15).