I suspect what you're referring to is a Top Hat. The tall black hats that gentlemen wear to formal occasions.
if you have an opera hat case
If by 'opera hat' you mean a top hat, it might be collapsible, which would make it easy to pack. Read more, below.
I would call it a hard hat
musical, opera maybe?
The Bowler and the Derby is the same hat. The British call the hat a Bowler. The Americans call the hat a Derby.
A Place to Call Home - opera - was created in 1993.
A "top hat" is a type of hat that is often associated with magicians, so in this case, you would call it a "sitting top hat."
In opera, the text is written by a librettist.
A Panama hat.
The libretto.
It's called a homburg hat
rizal wears a bowler hat.