The term 'Rounded TOPPER' is a combination of two crossword solutions: 'DERBY' (5 letters) and 'TOPPER' (7 letters). A DERBY is a type of hat, usually made of felt, with a rounded crown and a narrow brim. It is often associated with formal occasions such as horse racing events. A TOPPER is a type of hat that is worn on top of the head and is usually made of a stiff material such as straw or felt. Combining these two terms, 'Rounded TOPPER' refers to a hat that has a rounded crown and a stiff brim.