what is self defense ?

self defense is the set of joint lock techniques used in the martial arts to control or lock an opponent's joints or muscles/tendons so he cannot move, thus neutralizing the opponent's fighting ability.
the act of defending one's person when physically attacked, as by countering blows or overcoming an assailant:
the art of self-defense.
a claim or plea that the use of force or injuring or killing another was necessary in defending one's own person from physical attack:
He shot the man who was trying to stab him and pleaded self-defense at the murder trial.
an act or instance of defending or protecting one's own interests, property, ideas, etc.,
There are many facets when teaching self defense .Some types of self defense classes are shortened sessions from different martial art styles with an assortment of self defense techniques. ... Other styles of martial arts focus on grappling and ground fighting such as Jujitsu, wrestling, Judo, jeet kune do, wing chun kung fu & shaolin chin na.