Which style of dress has a fitted bodice and a straight skirt, often used for formal occasions?

The sheath dress is characterized by its fitted bodice and straight skirt, making it a popular choice for formal occasions. Its design closely follows the natural body shape without excess fabric, which creates a sleek and elegant silhouette. The contouring of the dress enhances the body's curves while providing a clean, polished look, suitable for events such as cocktail parties, weddings, and business functions.

This style contrasts with others, as the empire and dropped waist dresses have distinct features that do not align with the fitted bodice and straight lines of the sheath. An empire waist typically has a higher waistline that sits just under the bust, while a dropped waist falls below the natural waist, often creating a more relaxed and flowing garment. The shift dress, although also fitted, is generally looser and more forgiving around the waist and hips, diverging from the tailored aspect of the sheath design. Thus, the sheath dress stands out as the quintessential choice for a form-fitting, structured design suited for formal settings.