It originated in the United Kingdom, and is celebrated in a number of countries that previously formed part of the British Empire. Boxing Day is on December 26, although the attached bank holiday or public holiday may take place either on that day or two days later.
In the liturgical calendar of Western Christianity, Boxing Day is the second day of Christmastide, and also Saint Stephen’s Day It is also celebrated as Saint Stephen’s Day in Ireland and the Catalonia region of Spain. In some European countries, such as Romania, Hungary, Germany, Poland, the Netherlands, and Scandinavia, December 26 is celebrated as a Second Christmas Day.
There are competing theories for the origins of the term, none of which are definitive. The Oxford English Dictionary gives the earliest attestations from Britain in the 1830s, defining it as “the first week-day after Christmas-day, observed as a holiday on which post-men, errand-boys, and servants of various kinds expect to receive a Christmas-box.