landmark

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. A prominent identifying feature of a landscape.
2. n. A fixed marker, such as a concrete block, that indicates a boundary line.
3. n. An event marking an important stage of development or a turning point in history.
4. n. A building or site with historical significance, especially one marked for preservation by a municipal or national government.
5. adj. Having great import or significance: a landmark court ruling.
6. v. To accord the status of a landmark to; declare to be a landmark.

Century Dictionary and Cyclopedia

1. n. A boundary-mark to a tract of land; one of the fixed objects used to designate the limits of a farm, town, or other piece of territory, as monumental stones, marked trees, or ditches.
2. n. Any specific or prominent object marking a locality or historically associated with a locality; a hill, tree, house, or other feature of a landscape that may serve as a guide; especially, some object on land by which a locality may be recognized by persons at sea.
3. n. Figuratively, a distinguishing characteristic, variation, or event; that which marks a turning-point; something that serves to distinguish a particular period of time or point in progress or transition: as, the landmarks of science or history.

Wiktionary

1. n. A recognizable natural or man-made feature used for navigation.
2. n. A notable location with historical, cultural, or geographical significance.
3. n. A major, important event.
4. v. US To officially designate a site or building as a landmark.

GNU Webster's 1913

1. n. A mark to designate the boundary of land; any mark or fixed object (as a marked tree, a stone, a ditch, or a heap of stones) by which the limits of a farm, a town, or other portion of territory may be known and preserved.
2. n. Any conspicuous object on land that serves as a guide; some prominent object, as a hill or steeple.
3. n. A structure that has special significance, such as a building with historical associations a building that is protected from destruction or alteration by special laws intended to preserve structures of historical significance.
4. n. An event or accomplishment of great significance. Also used attributively, as a landmark court decision.

WordNet 3.0

1. n. an anatomical structure used as a point of origin in locating other anatomical structures (as in surgery) or as point from which measurements can be taken
2. n. an event marking a unique or important historical change of course or one on which important developments depend
3. n. the position of a prominent or well-known object in a particular landscape
4. n. a mark showing the boundary of a piece of land