From Middle English *landmark, from Old English landmearc (“boundary”) and Old English landġemirċe (“boundary, limit, frontier”), equivalent to land + mark. Cognate with German Landmarke (“landmark”), Danish landemærke (“landmark”), Swedish landmärke (“landmark”).
landmark (plural landmarks)
- A recognizable natural or man-made feature used for navigation.
- Anyone have any weird landmarks they often remember seeing along roads in the olden days? — 
- A notable location with historical, cultural, or geographical significance.
- Putting together a list of landmarks for Bangalore was not the easiest task." — 
- A major, important event.
- He called the overthrow of Iraqi dictator Saddam Hussein and the recent elections in Afghanistan landmark events in the history of liberty. — 
- (US) To officially designate a site or building as a landmark.
2007 March 25, Jeff Vandam, “Preservationists’ Rallying Cry”, in New York Times:
- “Permitted demolition or stripping rarely occurs on landmarked buildings,” she said. Ms. de Bourbon also noted that the city already requires the Buildings Department to hold permits for 40 days for “calendared” properties — those currently under landmarks consideration — so the commission has a chance to designate them.