'Black tie/Casablanca'

[docket]

Does anyone know what this means? Google is not very helpful on the subject. I have been invited to a ball in March, not my kind of thing at all but lots of people I know are going and it is for a good cause. I don't own a long evening dress and am hoping the 'Casablanca' thing hints at something more casual. Does anyone know?!!

I think it refers to the film casablanca. So that would late 1930s/early 1940s style clothes.

Yes, I agree with Rosy so sorry, no hint at casual: 30s/40s nightclub (which were so much more glamorous than nightclubs now).

do you have a camel coloured trenchcoat? or you could prob wear a tuxedo suit

see here