Oxymoron

[Page Stephens]

OXYMORON:
"A rhetorical figure in which an epigrammatic effect is created by the
conjunction of incongruous or contradictory terms"

Can anyone out there tell me when oxymoron lost its technical rhetorical
definition and became merely a synonym for a contradiction in terms?

For better or worse the former usage is apparently lost forever having been
overwhelmed by the popular usage to the point where no one except a
professor of English or someone like myself who took English back in the
middle ages would even know that it ever was a technical term.

Page Stephens