The term 'dressy dance' is a FORMAL event, usually involving dancing and dressing up in FORMAL attire. It is often held at a special venue such as a ballroom or banquet hall. The crossword solution for this term is 'FORMAL', which is an adjective meaning 'characterized by or requiring a neat, conventional, and dignified manner of dress or behavior'. This term is often used to describe events such as weddings, proms, and other special occasions.