Definitions
1.NounAn object that marks the boundary of a piece of land (usually a stone, or a tree).
2.NounA recognizable natural or man-made feature used for navigation.
3.NounA notable location with historical, cultural, or geographical significance.
4.NounA major event or discovery."an important landmark in human history; a landmark paper in neurosurgery; a landmark ruling/case"
5.VerbTo officially designate a site or building as a landmark.