Neckline

The neckline is the top edge of a garment that surrounds the neck, especially from the front view. Neckline also refers to the overall line between all the layers of clothing and the neck and shoulders of a person, ignoring the unseen undergarments.
For each garment worn above the waist, the neckline is primarily a style line and may be a boundary for further shaping of the upper edge of a garment with, for example, a collar, cowl, darts, or pleats. In that respect it is similar to the waistline and hemline.
List of neckline types.
Necklines can be grouped into categories according to their shape and where they cut across the body:
Modifications of necklines.
The shape of a necklines can be modified in many ways, e.g., by adding a collar or scarf, overlaying it with a gauzy material or decorating the edges with scallops, picots or ruffles. The neckline can be a sharp edge of fabric or a more gentle cowl, and can also be accentuated by pattern(s) in the fabric itself.
Ruffs were popular in the Elizabethan era.
Trends.
Off-the-shoulders.
The off-the-shoulder trend dates back to the Regency and Victorian Era. They were the height of fashion in the early to mid-nineteenth century. Charles Frederick Worth, the father of haute couture, designed many elaborate dresses, many of which featured bodices with off-the-shoulder sleeves and were very popular with prominent figures like . Then in 1960s, French actress Brigitte Bardot put her own twist on this style, wearing off-the-shoulder tops with everything from midi skirts to pants, reviving the style. The style icon made off-the-shoulder sexy and trendy again and off-the-shoulder style also became known as the “Bardot” style.