Meaning of "Hindenburg line" in the English dictionary

The Siegfriedstellung was a German defensive position of World War I, built during the winter of 1916–1917 on the Western Front, from Arras to Laffaux, near Soissons on the Aisne. In 1916 the Brusilov Offensive had inflicted huge losses on the Austro-Hungarian armies in Russia and forced the German eastern armies to take over more of the Eastern Front. The declaration of war by Romania had placed additional strain on the German war economy and army. The German offensive at Verdun had been a costly failure and Anglo-French attacks on the Western Front had inflicted serious losses on the German army, during the French counter-offensive at Verdun and the joint offensive on the Somme. Construction of the Siegfriedstellung had begun in September 1916 and was intended to counter an anticipated increase in the power of Anglo-French attacks in 1917. The shorter defensive position behind the Noyon Salient was built to contain an Allied breakthrough and make possible a deliberate withdrawal to prepared positions, which would also economise on manpower.