an act or instance of knocking out.
the state or fact of being knocked out.
Informal. a person or thing overwhelmingly attractive, appealing, or successful.
a panel in a casing, can, or box, especially of metal or plastic, so designed that it can readily be removed, as by punching, hammering, or cutting, to provide an opening into the interior: a knockout in a junction box.
Machinery. a device for knocking something loose, as finished work from a lathe chuck.
that knocks out: the knockout punch.
1810–20; 1935–40 for def 4; noun, adj. use of verb phrase knock out