Noun
deerstalker hat (plural deerstalker hats)
A type of men's headwear, made of cloth with a plaid pattern, having two projecting brims (one at the front and one at the back) and earflaps which can be folded up and tied at the top.
Synonyms: fore-and-after, hunting cap
Two famous fictional characters who wore deerstalker hats were Sherlock Holmes and Holden Caulfield in J. D. Salinger's Catcher in the Rye.