barn, n.¹ — Green’s Dictionary of Slang

barn n.¹

[Highbury Barn, north London, site of one of the last such venues]

a public ballroom.

1909		J. Ware Passing Eng. of the Victorian Era.
1977		A. Ayckbourn Ten Times Table I i: Yes, well, it’s a bit of a barn, I’m afraid. But it’s cheap. They don’t have so many dances these days.