A building in which a union meets or conducts its business; specifically the headquarters of a trade union used as a centre for meetings, for the recruitment of union workers, etc. (now chiefly US).
Origin
Early 19th century.
Definition of union hall in US English:
union hall
noun
A building in which a union meets or conducts its business; specifically the headquarters of a trade union used as a centre for meetings, for the recruitment of union workers, etc. (now chiefly US).