What does Boxing Day have to do with boxing?
1550s, "medical extract of flowers," from French anthère, from Modern Latin anthera "a medicine extracted from a flower," from Greek anthera, fem. of antheros "flowery, blooming," from anthos "flower," from PIE root *andh- "to bloom" (cf. Sanskrit andhas "herb," Armenian and "field," Middle Irish ainder "young girl," Welsh anner "young cow"). Main modern sense attested by 1791.
The pollen-bearing part at the upper end of the stamen of a flower. Most anthers occur at the tip of a slender, stemlike filament and have two lobes. Each lobe contains two pollen sacs. When pollen matures in the pollen sacs, the lobes of the anthers burst open in the process known as dehiscence to release the pollen. See more at flower.