Definition of UNION

the act or an instance of joining two or more things into one <the union of East Germany and West Germany that became possible after the fall of communism>
an association of persons, parties, or states for mutual assistance and protection <in 1949 the U.S. and Canada joined their European allies in a transatlantic union to defend Western Europe from aggression by the Soviet Union>
the state of having shared interests or efforts (as in social or business matters) <the movie studio is producing the blockbuster in union with another studio because of the tremendous cost involved>

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