foothold

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”

a place providing support for the foot in standing or climbing

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”