1. A most important event or decision. A turning point. 2. A building or mark on property that is easy to locate and has some significance such as being a boundary or may be of historical significance. A monument or erection set up on the boundary line of two adjoining-estates, to fix such boundary. The removing of a landmark is a wrong for which an action lies.
LANDMARK
TheLaw.com Law Dictionary & Black's Law Dictionary 2nd Ed.