What does Boxing Day have to do with boxing?
mid-14c., "decision, sentence," from Old French déterminacion (14c.) "determination, settlement, definition," from Latin determinationem (nominative determinatio) "conclusion, boundary," noun of action from past participle stem of determinare (see determine).
As "a bringing to an end" (especilly of a suit at law), late 15c. As "fixed direction toward a goal," from 1650s, originally in physics or anatomy; metaphoric sense "fixation of will" is from 1680s; that of "quality of being resolute" is from 1822.
determination de·ter·mi·na·tion (dĭ-tûr'mə-nā'shən)
A change for the better or for the worse in the course of a disease.
A fixed movement or tendency toward an object or end.
The ascertaining of the quantity, quality, position, or character of something.