The term "neckline" refers to the line that defines where a garment, such as a blouse or dress, begins at the neck and extends downward. It is typically characterized by the shape, style, and design details of the top part of an article of clothing. The neckline can vary greatly in terms of its depth, width, and overall appearance, ranging from simple V-necks to more elaborate designs such as deep plunges or high collars.