From Longman Dictionary of Contemporary Englishexpeditionary forceˌexpeˈditionary force noun [countable] PMAa group of soldiers that is sent to another country to fight in a war
Examples from the Corpus
expeditionary force• Christopher then embarked on a diatribe about the difficulties of an expeditionary force in hiatus.• In September Parliament sent an expeditionary force against them, under Warwick as admiral.• The last gamble, which would make concession unnecessary, was a new expeditionary force to defeat the rebels.• The Nanny Ogg expeditionary force corkscrewed up the spiral staircase.• Dalek firepower threatens to destroy the expeditionary force until the attackers hit on the idea of disabling the city's power generators. 