Boxing Day is the name given in England to the day after Christmas. Strictly speaking, Boxing Day is the first weekday after Christmas day.
The Woodlands Middle School website explains how Boxing Day got its name. One explanation of Boxing Day was the custom of the lord and lady of the manor “boxing” the surplus food and gifts left over from Christmas Day, to distribute them among the tenants who lived and worked on their land. This was usually done on the day after Christmas, which then got the name of Boxing Day.
Another instance was the Church encouraging people to donate gifts for the poor in the run-up to Christmas. The gifts were stored in a big alms box which was kept under lock and key. Then on the day after Christmas the box was opened and the gifts were distributed to the poor.
Another version had to do with the great sailing ships. Before the ship set sail on a long voyage, a box or container was placed on board, usually by a priest, for the sailors to donate gifts of money to ensure a safe return. The box was then sealed, and kept on board during the voyage.
If the ship returned safely, the box was handed over to the priest, who would offer a Mass of thanksgiving for the safe voyage. The priest would keep the box sealed until the day after Christmas, when it would be opened and the contents shared among the poor.
The day after Christmas Day is also known as Saint Stephen’s Day, in memory of the first martyr put to death for his faith in Jesus Christ. The story of Stephen’s trial and death is found in chapters 6 and 7 of the Acts of the Apostles.
The Church chose the day immediately after Christmas to commemorate the martyrdom of Saint Stephen. Perhaps that is to remind us that the baby born in Bethlehem on Christmas Day will also give his life one day to show mankind that God loves them.