fancy ball
Noun
Meaning
fancy ball (plural fancy balls)
(dated) A ball where guests come in fancy dress.
Examples
Now, a fancy ball is bad enough in London, where milliners are many, and where theatres have costumes that may be borrowed or copied; but in the country, where people are left to their own devices-truly to them may be applied the old poet's account of murderers, "their fancies are all frightful.”.