Law is the system of rules created and enforced by social or governmental institutions to regulate human conduct. The precise definition of law is a topic of long-standing debate, and varying interpretations have led to the creation of numerous legal systems.

Law can be divided into two broad categories: civil and criminal. Civil laws deal with property rights and personal relationships, while criminal laws address the actions of individuals in violation of society’s moral standards. A nation’s political climate can influence the type of laws that are made and enforced, as reflected in the fact that different countries have very different systems of civil and criminal law.

The purpose of law is to guide human behavior in a way that promotes stability and peace. As such, the role of law must be constantly evaluated to ensure that it is providing the appropriate balance between individual liberty and societal protections. In some cases, the balance may be achieved through the courts, which provide an opportunity for those who believe they are a victim of injustice to express their views before the decision-makers.

Several terms are important to understand when studying the legal system:

case law – The use of prior court decisions to determine how other law (such as statutes) should apply in a particular situation. Usually, a higher court’s decision is binding on lower courts unless there is compelling evidence or significantly different facts or issues. For example, all federal courts are bound by the Supreme Court’s decisions.

code of ethics – A set of principles that lawyers follow to govern their behavior and to help ensure the fairness of the legal process. Most states have codes of ethics that must be followed by all attorneys licensed to practice law in their jurisdiction.

counterclaim – A claim that the defendant makes against the plaintiff. These claims are often considered in the same proceedings as the plaintiff’s claims. court reporter – A person who makes a word-for-word record of what is said in court and produces a transcript of the proceedings upon request.

complaint – A written statement alleging that someone has done something illegal. This document is a formal request for a judge to hear the case.

defendant – The person accused of a crime. Defendants must be represented by a lawyer in a criminal case, but they can represent themselves (“pro se”) in civil cases.

conviction – A finding that the defendant has committed a crime. The judge must have sufficient evidence to prove the defendant’s guilt beyond a reasonable doubt before he or she can find the defendant guilty.

the rule of law – A principle that requires all persons and institutions, including governments, to be subject to laws that are publicly promulgated, equally enforced, and independently adjudicated and that comply with international human rights norms and standards. The rule of law encompasses a number of principles, such as supremacy of the law, equality before the law, accountability to the law, separation of powers, participation in the rule of law, and avoidance of arbitrariness.