Flanks of a frontier

Definitions

  • Webster's Revised Unabridged Dictionary
    • Flanks of a frontier salient points in a national boundary, strengthened to protect the frontier against hostile incursion.
    • ***

Usage

In literature:

The Germans were now on the alert to entrap this army that exposed its flank in a long line of march near to the Belgian frontier.
"The Development of the European Nations, 1870-1914 (5th ed.)" by John Holland Rose
***