bridge·head 
(brĭjhĕd′)
(brĭjhĕd′)n.
1.
a. A fortified position from which troops defend the end of a bridge nearest the enemy.
b. A forward position seized by advancing troops in enemy territory as a foothold for further advance.
2. The area immediately adjacent to the end of a bridge.
[Translation of French tête de pont : tête, head + de, of + pont, bridge.]