A certain neckline is a type of clothing design that is used to shape the neckline of a garment. The two most common types of certain necklines are VEE and VSHAPE. VEE is a neckline that is shaped like the letter 'V' and is usually cut low in the front. VSHAPE is a neckline that is shaped like an inverted 'V' and is usually cut higher in the front. Both of these necklines can be used to create a flattering look for any outfit.