What is the most likely origin of the word ten-gallon hat?

The gallon in 10-gallon most likely came from an anglicized version of a Spanish word cowboys picked up from their Mexican counterparts who wore braided hatbands on their sombreros called galóns. A 10-galón sombrero was a hat with a crown large enough to have a hatband with ten braids. It may have come from another Spanish phrase, tan galan, meaning “so gallant,” another reference to the appearance of an impressive hat. Either way, a 10-gallon hat is not a measurement of volume.