The straight neckline is a clean line across the chest, which is used very often on strapless gowns. It is quite a simple neckline which works very well for small busts, especially when the bodice is ruched or pleated.
This neckline is widely used for strapless dresses. It dips slightly in the middle, and looks like the top of the heart shape. This neckline is very flattering for bigger busts.
This neckline can vary in style. It can be either simple and conservative or plunge daringly to the belly button. It is also often used for halter neck gowns. It is a very comfortable neckline as it usually comes with straps or sleeves.
The scoopneck neckline usually comes with straps and creates a very gentle silhouette. However there are some strapless gowns that have this soft rounded neckline that dips slightly in the middle.
This is quite a strict and demure shape. The boatneck is high on the chest and cuts almost in a straight line from shoulder to shoulder. A small tip in case you plan to wear a necklace with this neckline, it might fall behind the fabric.
This neckline has many different styles. One of the common looks is where the turtleneck continues down and under the arms, thus baring the shoulders. This look can be quite strict and goes well for brides with toned upper body and small bust. Another more traditional and conservative interpretation is a lace turtleneck that turns into a cap-sleeved top, which covers the chest and drapes the bodice of the gown.