A landmark is an event, discovery, development or change that marks an important stage in something. In a legal context, it is most commonly used in the phrase “landmark case”, also called a landmark decision or a seminal case. A landmark case is a court decision that establishes an important new legal principle or concept, or which changes the previous interpretation of current law. They are a part of case law, which is law that comes from the decisions of courts as opposed to legislation.
For example, the United States Supreme Court has a long history of landmark cases covering everything from due process (the principle that government must respect all citizens’ legal rights during the course of legal proceedings) to the right to counsel to equal protection and segregation.
In addition, landmark can also be used to describe a building, structure or feature of a landscape or town that can be seen from a distance and which can be used by people to help find out where they are. For example, Edinburgh Castle is one of the most famous landmarks in Scotland.