Ma ‧ gi ‧ not Line, the /ˈmæʒənəʊ ˌlaɪn, ˈmæʒɪnəʊ ˌlaɪn/ BrE AmE
a line of ↑ fort s (=very strong buildings for use by an army) built before World War II to defend the eastern border of France against the Germans. It was not effective, because the German army avoided it by going through Belgium. ⇨ compare ↑ Siegfried Line