What does Boxing Day have to do with boxing?
c.1300, "exit, a going out, flowing out," from Old French issue "a way out, exit," from fem. past participle of issir "to go out," from Latin exire (cf. Italian uscire, Catalan exir), from ex- "out" (see ex-) + ire "to go," from PIE root *ei- "to go" (see ion). Meaning "discharge of blood or other fluid from the body" is from 1520s; sense of "offspring" is from late 14c. Meaning "outcome of an action" is attested from late 14c., probably from French; legal sense of "point in question at the conclusion of the presentation by both parties in a suit" (early 14c. in Anglo-French) led to transferred sense of "a point to be decided" (1836). Meaning "action of sending into publication or circulation" is from 1833.
c.1300, "to flow out," from issue (n.) or else from Old French issu, past participle of issir; sense of "to send out authoritatively" is from c.1600; that of "to supply (someone with something)" is from 1925. Related: Issued; issuing.
issue is·sue (ĭsh'ōō)
A discharge, as of blood or pus.
A lesion, a wound, or an ulcer that produces a discharge of this sort.
A problem •Colloquial: We have an issue with irregular newspaper delivery