A boundary line indicated by a stone, stake, etc. (Deuteronomy 19:14; 27:17; Proverbs 22:28; 23:10; Job 24:2). Landmarks could not be removed without incurring the severe displeasure of God.

Noah Webster's New International Dictionary of the English Language

1. (n.) Any conspicuous object on land that serves as a guide; some prominent object, as a hill or steeple.

2. (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.