The United States has many court systems. Each states has its own court system. and there is also a system of federal courts. Each of these systems has trial and appeals courts. There are also a number of tribal justice systems. The highest court in the land is the Supreme court of the United States. The Supreme Court hears appeals from the other court system.
Trial courts listen to testimony, consider evidence, and decide the facts in disputed situations. Evidence is provided by witnesses who are called to testify in the case. In a trial there are two parties, or sides, to each case. In a civil trial, the party bringing the legal action is called the plaintiff. In a criminal trial, the government (state or federal) initiates the case and serves as the prosecutor. In both civil and criminal trials, the party responding to the plaintiff(civil) or prosecution (civil) or prosecution(criminal) is called the defendant. Once a trial court has made a decision, the losing party may b able to appeal the decision to an appellate, or appeals, court.