the.com/flat cap

means A rounded, stiff-brimmed cap with a small peak, cut from one piece of fabric and sewn to lie flat on top.

from Rooted in English working headwear going back centuries, the flat cap became especially associated with laborers, farmers, and northern English workingmen by the 19th century — practical, cheap wool or tweed that kept rain off without the fuss of a brim all round. England even had old sumptuary-style customs encouraging commoners to wear wool caps like this. It later drifted upmarket, adopted for golf, hunting, and country tweeds by the gentry, which is how a cap born in the mill town ended up on the grouse moor.