foothold

(n) 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
bridgehead,
(n) a place providing support for the foot in standing or climbing footing,
(n) 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
beachhead,

bridgehead footing beachhead