The Ten Gallon Hat
Holds Less Than A Gallon of Water
The term "ten-gallon hat" is a bit of a misnomer and doesn't refer to the hat's capacity. There are a few theories about the origin of this name:
One popular theory is that the term "ten-gallon" comes from a misunderstanding or anglicization of the Spanish word "galón," which means "braid." The hats were often decorated with braided bands, and a "ten-galón" hat would be one with a wide decorative band.
Another theory is that the term "ten-gallon" was used as a form of hyperbole to emphasize the hat's large size. It was a way to make the hat sound more impressive.
Some believe that the term was coined or popularized by advertising campaigns in the early 20th century to evoke images of the rugged cowboy lifestyle and to sell more hats.
A ten-gallon hat does not actually hold ten gallons of liquid. In fact, a ten-gallon hat holds less than a gallon of water. The name has stuck, however, and it is now synonymous with the large, wide-brimmed cowboy hats associated with the American West.