Defile (geography)

In geography, a defile is a narrow pass or gorge between mountains or hills.

[1] On emerging from a defile (or something similar) into open country, soldiers are said to "debouch".

[3] Defiles of military significance can also be formed by other physical features that flank a pass or path and cause it to narrow, for example impassable woods and rivers.

[4] Some defiles have a permanent strategic importance and become known by that term in military literature.

For example, the military historian William Siborne names such a geographic feature in France near the frontier with Germany in his book Waterloo Campaign 1815: On the following day, General Rapp fell back upon the Defile of Brümath; but this he quitted in the night, and took up a favourable position in the rear of the Suffel, near Strasburg.