Boxing Day is the day after Christmas, a public holiday in most countries in the Commonwealth. It is usually celebrated on 26 December, the day after Christmas but can move to the next weekday if 26 December is a Saturday or Sunday.
Not this kind of boxing!
A Christmas box is, in English tradition, a clay box used in artisan shops. Apprentices, masters, visitors, customers, and others would put donations of money into the box, like a piggy bank, and then, after Christmas, the box would be shattered and all the contents shared among the workers of the shop. Thus, masters and customers could donate bonuses to the workers without anything direct, and the employees could average their wages. The habit of breaking the Christmas box lent its name to Boxing Day.
In feudal times, Christmas was a reason for a gathering of extended families. All the serfs would gather their families in the manor of their lord, which made it easier for the lord of the estate to hand out annual stipends to the serfs. On 26th December, after all the Christmas parties, the lord of the manor would give practical goods such as cloth, grains, and tools to the serfs who lived on his land. Each family would receive a box full of such goods, hence “Boxing Day.” According to this tradition, the lord of the manor did not volunteer, but was obliged to supply these gifts.
In churches, it was traditional to open the church’s donation box on Christmas Day, and the money inside was to be distributed to the poorer or lower class citizens on the next day. In this case, the “box” in “Boxing Day” comes from that lockbox in which the donations were left.