A rule of conduct, generally found enacted in the form of a statute, that proscribes or mandates certain forms of behavior.

The written or codified law; the "law on the books," as enacted by a government body or agency having the power to make laws.

The written, organized, and compiled form of the criminal laws of a jurisdiction. 

The body of judicial precedent. historically built on legal reasoning and past interpretations of statutory laws, that serves as a guide to decision making. especially in the courts. 

The body of law originating from usage and custom rather than from written statutes. The term refers to an unwritten body of judicial opinion, originally developed by English courts, that is based on non-statutory customs, traditions, and precedents that help guide judicial decision-making. 

Rule of Law:

The maxim that an orderly society must be governed by established principles and known codes that are applied uniformly and fairly to all of its members.

Substantive criminal law:

The part of the law that defines crimes and specifies punishments.

The part of the law that specifies the methods to be used in enforcing substantive law.

The branch of modern law that governs relationships between parties.

Tort:

A wrongful act, damage, or injury not involving a breach of contract. Also, a private or civil wrong or injury.

A legal principle that ensures that previous judicial decisions are authoritatively considered and incorporated into future cases.

Stare Decisis:

The legal principle that requires that in subsequent cases on similar issues of law and fact, courts be bound by their own earlier decisions and by those of higher courts having jurisdiction over them. The term literally means ” standing by decided matters.”

Felony:

A criminal offense punishable by death or by incarceration in a prison facility for at least one year.

Misdemeanor:

An offense pun ishable by incarceration, usually in a local confinement facility, for a period whose upper limit is prescribed by statute in a given jurisdiction, typically one year or less.

Offense:

A violation of the criminal law. Also, in some jurisdictions, a minor crime, such as jaywalking, that is sometimes described as ticketable.

A minor violation of state statute or local ordinance punishable by a fine or other penalty or by a specified, usually limited, term of incarceration.

Espionage: 

The "gathering, transmitting, or losing" of information related to the national defense in such a manner that the information becomes available to enemies of the United States and may be used to their advantage.

A U.S. citizen’s actions to help a foreign government overthrow, make war against, or seriously injure the United States. Also, the attempt to overthrow  the government of the society of which one is a member.    

Inchoate offense: 

An offense not yet completed. Also, an offense that consists of an action or conduct that is a step toward the intended commission of another offense.

Actus reus: 

An act in violation of the law. Also, a guilty act.

The state of mind that accompanies a criminal act. Also, a guilty mind.

Reckless behavior: 

A behavior in which a person fails to reasonably perceive substantial and unjustifiable risks of dangerous consequences.

Motive: 

A person's reason for committing a crime.

Concurrence: 

The coexistence of (1) an act in violation of the law and (2) a culpable mental state.

Legal cause:

A legally recognizable cause. A legal cause must be demonstrated in court in order to hold an individual criminally liable for causing harm.

ex post facto: 

Latin for" after the fact." The Constitution prohibits the enactment of ex post facto laws, which make acts committed before the laws in question were passed punishable as crimes.

Attendant circumstances: 

The facts surrounding an event.

Element (of a crime):

In a specific crime, one of the essential features of that crime, as specified by law or statute.

corpus delicti: 

The facts that show that a crime has occurred. The term literally means "the body of the crime."

Islamic law: 

A system of laws, operative in some Arab countries, based on the Muslim religion and especially the holy book of Islam, the Koran.

Hudud crime:

A serious violation of Islamic law that is regarded as an offense against God.

Tazir crime: 

A minor violation of Islamic law that is regarded as an offense against society, not God.

Defense (to a criminal charge):

The evidence and arguments offered by a defendant and his or her attorney to show why the defendant should not be held liable for a criminal charge. 

Alibi:

A statement or contention by an individual charged with a crime that he or she was so distant when the crime was committed, or so engaged in other provable activities, that his or her participation in the commission of that crime was impossible. 

Justification: 

A legal defense in which the defendant admits to committing the act in question but claims it was necessary in order to avoid some greater evil. 

Excuse: 

A legal defense in which the defendant claims that some personal condition or circumstance at the time of the act was such that he or she should not be held accountable under the criminal law.

Procedural defense: 

A defense that claims that the defendant was in some significant way discriminated against in the justice process or that some important aspect of official procedure was not properly followed in the investigation or prosecution of the crime charged.

Self-defense: 

The protection of oneself or of one's property from unlawful injury or from the immediate risk of unlawful injury. Also, the justification that the person who committed an act that would otherwise constitute an offense reasonably believed that the act was necessary to protect self or property from immediate danger. 

Reasonable force: 

A degree of force that is appropriate in a given situation and is not excessive. Also, the minimum degree of force necessary to protect oneself, one's property, a third party, or the property of another in the face of a substantial threat.

Alter ego rule: 

In some jurisdictions, a rule of law that holds that a person can only defend a third party under circumstances and only to the degree that the third party could legally act on his or her own behalf.

A legal defense based on claims of mental illness or mental incapacity.

M'Naghten rule: 

A rule for determining insanity that asks whether the defendant knew what he or she was doing or whether the defendant knew that what he or she was doing was wrong.

Guilty but mentally ill (GBMI): 

A verdict, equivalent to a finding of "guilty," that establishes that the defendant, although mentally ill, was in sufficient possession of his or her faculties to be morally blameworthy for his or her acts.

A defense based on claims of a mental condition that may be insufficient to exonerate the defendant of guilt but that may be relevant to specific mental elements of certain crimes or degrees of crime.

Incompetent to stand trial: 

In criminal proceedings, a finding by a court that as a result of mental illness, defect, or disability, a defendant is incapable of understanding the nature of the charges and proceedings against him or her, of consulting with an attorney, and of aiding in his or her own defense.

Entrapment: 

An improper or illegal inducement to crime by agents of law enforcement. Also, a defense that may be raised when such inducements have occurred.

Double Jeopardy: 

A common law and constitutional prohibition against a second trial for the same offense.