The term 'neckline shapes' refers to the different types of shapes that can be used to create a neckline on a garment. One of the most popular neckline shapes is the V-neck, which is characterized by its V-shaped cut that dips down from the collarbone. This type of neckline is flattering on many body types and can be dressed up or down depending on the occasion. Other popular neckline shapes include the scoop neck, which is a rounded neckline that sits just below the collarbone, and the boat neck, which is a wide, straight neckline that sits just above the collarbone.