1.  beachhead(n = noun.location) - a bridgehead on the enemy's shoreline seized by an amphibious operation; "the Germans were desperately trying to contain the Anzio beachhead"
is a kind of bridgehead, foothold

2.  beachhead(n = noun.act) foothold - 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"
is a kind of accomplishment, achievement

   an area in hostile territory that has been occupied and is held to allow aditional troops and supplies to enter. [WordNet 1.5]

beachhead, n. Mil. a fortified position established on a beach by landing forces.

Etymology:
after bridgehead