Line or Border That Separates Two Countries
This page is the CodyCross answer for the clue below from Architectural Styles, Group 1165, Puzzle 2 (Symmetrical).
Question is: Line or Border That Separates Two Countries
and the answer is: FRONTIER
Word Meaning:
FRONTIER — The part of a country which borders or faces another country or unsettled region.
Definitions from Wiktionary.