What does Boxing Day have to do with boxing?
mid-15c., from Anglo-French donour, Old French doneur (Modern French donneur), from Latin donatorem (nominative donator) "giver, donor," agent noun from past participle stem of donare "give as a gift" (see donation). Of blood, from 1910; of organs or tissues, from 1918.
donor do·nor (dō'nər)
One from whom blood, tissue, or an organ is taken for use in a transfusion or transplant.
A chemical compound that can transfer an atom, a radical, or a particle to an acceptor.