"bridgeheads" in the noun sense
1. bridgehead, 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"
2. bridgehead
a defensive post at the end of a bridge nearest to the enemy
Source: WordNet® (An amazing lexical database of English)
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