The Brits and many parts of the Commonwealth (former empire) call the day after Christmas "Boxing Day." It is celebrated either on the 26th or the next weekday after Christmas if Christmas falls on Friday or Saturday.
This usage of "boxing" has nothing whatsoever to do with pugilism. It is believed named for the "box" or gift given to servants who were given the day after Christmas off to go visit their families. It may also refer to a gift given to the postman, dustman, or other functionary who provides relatively regular service to the household.
Interestingly, yearend tipping of the building super, doorman or postman is an East Coast thing in the U.S., particularly a New York City thing. It has not been widespread on the West Coast or, I believe, in the flyover country between the coasts, at least since World War II.
Some of this may be the relative rarity of condo and coop living and the lack of service provided to many renters. I spent nearly 15 years in West Coast rentals as a young person and never heard of anyone tipping a resident (or nonresident) manager, as they're typically called.
On the other hand, the only service they provided was rent collection, exterior maintenance and arranging for repairs in the event any interior system went "down." Mostly we were on our own (and preferred it).
