definition of boundaries
However, frontier sometimes refers to a different set, which is the set of boundary points which are not actually in the set; that is, S \ S. A connected component of the boundary of S is called a boundary component of S. Dictionary of Military and Associated Terms(0.00 / 0 votes)Rate this definition: boundary. A line that delineates surface areas for the purpose of facilitating coordination and deconfliction of operations between adjacent units, formations, or areas.