Cocktail attire is a semi-formal dress code bridging the gap between elegant and comfortable. It's dressier than business casual but less formal than black tie. The goal is to look polished, festive, and intentional without wearing a full-length evening gown or a tuxedo.
For men think sports coat and nice slacks.
For ladies, think knee-length, tea-length, or midi dresses or a dressy jumpsuit. Short dresses are fine too.