A beachhead refers to a secure area on a beach that is captured by soldiers during war or military operations. It serves as a starting point for further advancement or as a base for ongoing operations.
Its landmark decision was heralded as «a dramatic beachhead for the divestment movement» by American environmentalist Bill McKibben and has inspired universities across Britain and Europe to follow suit. (desmogblog.com)
The ants apparently establish beachheads in areas disturbed by human activity and then invade neighboring undisturbed areas. (sciencemag.org)