Glossary
Common law
Law made by judges in the course of deciding cases, rather than written by legislatures. Most U.S. states still use common law for many areas: torts, contracts, property: supplementing or overriding it with statutes as needed.
The common-law tradition descends from English law and characterizes the U.S. legal system. Courts decide a case, write an opinion explaining their reasoning, and that decision becomes a precedent that binds future courts in similar situations.
Over centuries, this case-by-case process produces a body of law that's never voted on by a legislature. Negligence law, much of contract law, and many property doctrines started as common law.
A legislature can override common law by passing a statute. But unless they do, the common-law rules established by past cases continue to govern.