Flat cap
From Tardis Wiki, the free Doctor Who reference
A flat cap was a type of hat.
Following his regeneration, the Third Doctor tried on a flat cap. Upon looking in a mirror, he decided against wearing it. (TV: Spearhead from Space [+]Loading...["Spearhead from Space (TV story)"])
Romana I wore a flat cap of tartan on her first visit to Earth. (TV: The Stones of Blood [+]Loading...["The Stones of Blood (TV story)"])
Wilfred Mott wore a flat cap of houndstooth tweed when he reunited with Donna Noble and the Doctor in his fourteenth incarnation. (TV: Wild Blue Yonder [+]Loading...["Wild Blue Yonder (TV story)"])