(of a clause) unable to stand alone syntactically as a complete sentence; "a subordinate (or dependent) clause functions as a noun or adjective or adverb within a sentence"
a defensive post at the end of a bridge nearest to the enemy
an area in hostile territory that has been captured and is held awaiting further troops and supplies; "an attempt to secure a bridgehead behind enemy lines"; "the only foothold left for British troops in Europe was Gibraltar"
an initial accomplishment that opens the way for further developments; "the town became a beachhead in the campaign to ban smoking outdoors"; "they are presently attempting to gain a foothold in the Russian market"
a bridgehead on the enemy's shoreline seized by an amphibious operation; "the Germans were desperately trying to contain the Anzio beachhead"