Определение dividing line в Английский Язык Английский Язык словарь
separating boundary, border used to separate two objects (or areas, time zones, etc.)
The dividing line between two areas is the boundary between them. people on both sides of the dividing line between Israel and the occupied territories. the difference between two similar things dividing line between
A dividing line is a distinction or set of distinctions which marks the difference between two types of thing or two groups. There's a very thin dividing line between joviality and hysteria