The Oxford English Dictionary records Boxing Day from 1743 as the day after Christmas, when tradespeople and employees received presents or gratuities called a Christmas box. Samuel Pepys noted the custom in his diary in December 1663. Servants, needed at work on Christmas itself, got the 26th off to visit family, carrying a box of gifts and leftovers.
An older layer: churches placed alms boxes for the poor and opened them on St. Stephen's Day, December 26, distributing the contents to the needy. The reference works admit the term's exact origin is not definitive; church box and servant box may both be true.
Nothing in the record connects the day to pugilism. The name's modern global meaning, doorbuster sales from Toronto to Sydney, dates to the late 20th-century retail calendar, a total inversion of a day built on giving money down the social ladder.
A day once reserved for tipping servants became a stampede for discounted televisions; when exactly did the box stop being for them?