What is Case Law?

Legal Definition
Case law is the set of existing rulings which made new interpretations of law and, therefore, can be cited as precedents. In some countries, such as the United States, the term is exclusively used for judicial decisions of selected appellate courts, courts of first instance, and other bodies discharging judicial functions. In other countries, such as most European countries, the term is applied to any set of rulings on law which is guided by previous rulings, for example, patent office case law. These interpretations are distinguished from statutory law which are the statutes and codes enacted by legislative bodies; regulatory law which are regulations established by governmental agencies based on statutes; and in some states, common law which are the generally accepted laws carried to the colonies and former colonies of England (USA, Australia, etc.). Trials and hearings which are not selected as 'courts of first impression' do not have rulings that become case law; therefore, these rulings cannot be precedents for future court decisions.

The legal systems of the Nordic countries are sometimes included among the civil law systems, but as a separate branch, and sometimes counted as separate from the civil law tradition. In Sweden, for instance, case law arguably plays a more important role than in some of the Continental civil law systems. The two highest courts, the Supreme Court (Högsta domstolen) and the Supreme Administrative Court (Regeringsrätten), have the right to set precedent which is in practice (however not formally) binding on all future application of the law. Courts of appeal, both general courts (hovrätter) and administrative courts (kammarrätter) may also issue decisions that act as guides for the application of the law, but these decisions may be overturned by higher courts.
-- Wikipedia
Legal Definition
A professional name for the aggregate of reported cases as forming a body of jurisprudence; or for the law of a particular subject as evidenced or formed by the adjudged cases; in distinction to statutes and other sources of law.
-- Black's Law Dictionary
Legal Definition
The law as laid down in the decisions of the courts.
-- Ballentine's Law Dictionary