1. a prominent or well-known object or feature that serves as a guide or reference point
2. a building or place that has historical importance or significance
3. an important event or development that marks a turning point

1. having great importance or significance, especially as a precedent

Examples

• The Statue of Liberty is a famous landmark in New York Harbor.
• We used the old oak tree as a landmark to find our way back.
• The courthouse is a protected historical landmark.
• The invention of the internet was a landmark in human communication.
• The Supreme Court’s landmark decision changed civil rights law.
• That tall building serves as a landmark for pilots.
• The peace treaty was a landmark achievement for both nations.