Many governments, such as the one in the United States, are divided into branches. A legislative branch is part responsible for making laws. Once those laws are created, the judicial branch determines what they mean, whether they have been broken, and what punishments should be issued when they are broken. A court of law is the place where most judicial activity takes place.
Courts of law can generally be described as society’s decision makers. Most cases brought before a court involve at least two parties: there is usually a plaintiff, the party that brings a complaint, and a defendant, the party that needs to defend itself against the complaint. The matters being disputed can be either criminal or civil.
In some instances, a judge or a magistrate hears cases and makes a decision, which is commonly referred to as a ruling. In other instances, a body of individuals from the community is chosen to compose a jury. The jury is then given the task of hearing the case and making a decision. A "court of law" is called so because a judge or jury does not simply make decisions pertaining to a case based on what they believe to be best or what they want to happen. Their decisions must be based on the law.
In some instances, such as with a supreme court, it is the duty of the officials to interpret the law. Such a court may find that a law itself is unconstitutional and needs to be removed. Although these officials did not write the law, it may decide that its wording gives it a meaning that differs from the intentions of the people who did write it.
When it is determined in a court of law that an individual has committed an illegal act, the court has the authority to issue a punishment. In some instances, the law dictates the minimum or maximum punishments that can be imposed. When a punishment, which is commonly referred to as a sentence in criminal cases, is issued, it is generally binding unless it is overturned by way of an appeal. An appeal is a process which allows one court to change the decision of a lower one.
Courts are usually limited by some type of jurisdiction, which means they only have the power to hear and decide cases that fit certain criteria. A bankruptcy court, for example, can only hear cases pertaining to bankruptcy. Beyond that, the officials have no authority over legal matters. A general district court of law usually has the ability to hear a wide range of cases; however, its jurisdiction is limited to the district in which the court sits.