The term 'Wester (Hat)' can be summarized as a type of hat that was popular in the 19th century, particularly in the American West. The term is derived from the word 'WESTERN, ' and the hat was typically made of felt and had a wide brim. It was often worn by cowboys and other people living in the WESTERN United States. The crossword solution for this term is SOU, which stands for 'Stetson Open-Crowned.' This refers to the Stetson brand of hats, which were popular in the 19th century and are still produced today.