The story
From the stage adaptation of George du Maurier's novel Trilby, in which such hats were worn.
Etymology from Wiktionary, CC BY-SA 4.0.
Today it means: narrow-brimmed type of felt hat, described as having a "shorter brim which is angled down at the front and slightly turned up at the back" in comparison to the fedora Full definition →
From the stage adaptation of George du Maurier's novel Trilby, in which such hats were worn.
Etymology from Wiktionary, CC BY-SA 4.0.