The term 'PART OF USA' can be broken down into four crossword solutions: STATES (6 letters), AMER (4 letters), UNITED (6 letters), and AMERICA (7 letters). STATES refers to the individual states that make up the UNITED States of America, such as California, Texas, and New York. AMER is an abbreviation for America, which is the name of the continent on which the UNITED States is located. UNITED is an adjective used to describe the UNITED States, which is a union of 50 states and other territories. AMERICA is the name of the entire continent, which includes the UNITED States, Canada, Mexico, and other countries.