https://en.wikipedia.org/wiki/Boxing_Day
There are competing theories for the origins of the term, none of which are definitive.[6]
The European tradition of giving money and other gifts to those in need, or in service positions, has been dated to the Middle Ages, but the exact origin is unknown. It is sometimes believed to be in reference to the Alms Box placed in the narthex of Christian churches to collect donations to the poor. The tradition may come from a custom in the late Roman/early Christian era wherein alms boxes placed in churches were used to collect special offerings tied to the Feast of Saint Stephen,[7] which, in the Western Christian Churches, falls on the same day as Boxing Day, the second day of Christmastide. On this day, it is customary in some localities for the alms boxes to be opened and distributed to the poor.[1][8]
Sounds like your definition isn't definitive.