A trilby is a style of hat with a small brim. The trilby, often known as the "brown trilby" in Britain, was previously thought to be the preferred hat of the wealthy and was regularly spotted at horse races.
In contrast to the fedora's wider brim, the trilby has a shorter brim, which is angled down at the front and somewhat turned up at the back. The trilby's crown is also a little bit shorter than a typical fedora's.
The theater adaptation of George du Maurier's 1894 novel Trilby is where the hat gets its name. When this hat was worn in the play's first London production, it was quickly referred to as "a Trilby hat.
Trilby hats were associated with Frank Sinatra, and one of his hallmark styles even bears his name.