A knockout is a fight-ending, winning criterion in several full-contact combat sports, such as boxing, kickboxing, muay thai, mixed martial arts, karate, some forms of taekwondo and other sports involving striking, as well as fighting-based video games. A full knockout is considered any legal strike or combination thereof that renders an opponent unable to continue fighting.
Ingemar Johansson knocks Floyd Patterson out, becoming boxing heavyweight champion of the world, on June 26, 1959.
A heavy blow to the head is a frequent cause of a knockout. Muhammad Ali delivers one to Brian London and retains his heavyweight championship by third-round KO on August 6, 1966.
The referee may stop a match if they deem either competitor unable to fight.
A knockout can be characterized by unconsciousness.
Boxing is a combat sport and a martial art in which two people, usually wearing protective gloves and other protective equipment such as hand wraps and mouthguards, throw punches at each other for a predetermined amount of time in a boxing ring.
Two Royal Navy men boxing for charity (1945). The modern sport was codified in England in the 19th and early 20th centuries.
A painting of Minoan youths boxing, from an Akrotiri fresco circa 1650 BC. This is the earliest documented use of boxing gloves.
A boxing scene depicted on a Panathenaic amphora from Ancient Greece, circa 336 BC, British Museum
A boxer and a rooster in a Roman mosaic of first century AD at the National Archaeological Museum, Naples
