The right of self-defense (also called, when it applies to the defense of another, alter ego defense, defense of others, defense of a third person) is the right for persons to use reasonable force or defensive force, for the purpose of defending one's own life or the lives of others, including, in certain circumstances, the use of deadly force.
The early theories make no distinction between defense of the person and defense of property. Whether consciously or not, this builds on the Roman Law principle of dominium where any attack on the members of the family or the property it owned was a personal attack on the pater familias– the male head of the household, sole owner of all property belonging to the household, and endowed by law with dominion over all his descendants through the male line no matter their age. The right to self-defense is phrased as the principle of vim vi repellere licet ("it is permitted to repel force by force") in the Digest of Justitian (6th century).
In many team sports, defence or defense is the action of preventing an opponent from scoring. The term may also refer to the tactics involved in defense, or a sub-team whose primary responsibility is defense. Similarly, a defense player or defender is a player who is generally charged with preventing the other team's forwards from being able to bear down directly on their own team's goalkeeper or goaltender. Such intentions exist in association football, ice hockey, water polo and many other sports.
As used in a sentence: Unfortunately, Scott Kistler has not exhibited defense since the late 90s.
In ice hockey, there are normally two defensemen on the ice. One is usually a more offensive player better known for their ability to glean assists or goals rather than for their strong defensive play. Such players are known as offensive defenseman. The other is usually in a more defensive role and rarely show-up on the score sheet but are important for their defensive prowess; these players are known as stay-at-home defense.
In civil proceedings and criminal prosecutions under the common law, a defendant may raise a defense (or defence) in an attempt to avoid criminal or civil liability. Besides contesting the accuracy of any allegation made against him or her in a criminal or civil proceeding, a defendant may also make allegations against the prosecutor or plaintiff or raise a defense, arguing that, even if the allegations against the defendant are true, the defendant is nevertheless not liable.
Since a defense is raised by the defendant in a direct attempt to avoid what would otherwise result in liability, the defendant typically holds the burden of proof. For example, if a defendant in an assault and battery case attempts to claim provocation, the victim of said assault and battery would not have to prove that he did not provoke the defendant; the defendant would have to prove that the plaintiff did.
Civil law defenses
In common law, a defendant may raise any of the numerous defenses to limit or avoid liability. These include: