The answer to the crossword is ARIA, a 4-letter Vegas resort with a musical name. ARIA Resort & Casino is located on the Las Vegas Strip and is one of the most luxurious resorts in the city. It is known for its modern architecture, world-class restaurants, and entertainment venues. The resort also features a casino, spa, and pool. The name ARIA is derived from the Italian word for air, which reflects the resort's modern design.