What does Boxing Day have to do with boxing?
mid-15c., "light-colored wine," from Old French (vin) claret "clear (wine), light-colored red wine" (also "sweetened wine," a sense in English from late 14c.), from Latin clarus "clear" (see clear (adj.)). Narrowed English meaning "red wine of Bordeaux" (excluding burgundy) first attested 1700. Used in pugilistic slang for "blood" from c.1600.
[1604+ Prizefight; fr the red color of claret wine]
any of numerous wines of the region surrounding the city of Bordeaux, France. Bordeaux has a long history in wine culture; like Burgundy and the Rhine region, it was known in Roman times. During the English occupation of Bordeaux, a charter was granted, first by Richard I and second by John in 1199, to the still-functioning jurade, a controlling body dating originally from the 12th century, which in its ceremonies still observes its medieval ritual and uses its traditional robes of the St. Emilion district for the supervision of wine making. Claret meant in those days a pale wine made by mixing reds and whites; the word claret is not used in modern French