What is Common Law?
Wikipedia states:
In law, common law (also known as judicial precedent or judge-made law, or case law) is the body of law created by judges and similar quasi-judicial tribunals by virtue of being stated in written opinions.
The defining characteristic of “common law” is that it arises as precedent. In cases where the parties disagree on what the law is, a common law court looks to past precedential decisions of relevant courts, and synthesizes the principles of those past cases as applicable to the current facts. If a similar dispute has been resolved in the past, the court is usually bound to follow the reasoning used in the prior decision (a principle known as stare decisis).