Think of your face as a picture and the neckline a frame. Your neckline is probably the feature you’ll zero in on most when choosing your dress. It’s the part of your gown that gives your face that wow factor. Because there are almost as many neckline as sleeve variations, think of mixing both components as an opportunity to really create that one-of-a-kind gown. Keep in mind, front and back necklines aren’t always identical. For instance, the front could have a Sabrina neckline while the back plunges into a deep V; whereas another gown could have a scoop in front as well as back.
Turtleneck-Pictured directly below. Once a classic, the high neck or turtleneck can be a plain band of dress fabric or lace. Especially popular with the Prairie Revival gown craze of the 70s when cotton ‘granny gowns’ reappeared.

Mandarin-Like the high neck collar only it’s notched in front
Cowl-Pictured above, the cowl is draped either as an attached piece or integrated into the pattern. Lots of retro styles of the 1930s use this effect.
Jewel-Aka crew neck, round and higher neckline. Not seen too much these days except in an over bodice of all-over lace.
Bateau or Sabrina-Pictured directly below, this neckline is straight across.
                                                       Scoop-Low rounded neckline

V or U-These necklines point down just like the letters they are named after.

        Scoop-Low rounded neckline
Off-the-Shoulder-Neckline extends horizontally across and sits below the shoulders.

Square-One of my personal favorites, conveying a real open look, square necks look great on long and A-line silhouettes.
Portrait-Wide band that extends from shoulder to shoulder
Halter-Straps either wrap around the neck or neckline is high with deep armholes.
Strap-Usually holds up a strapless bodice.
Asymmetrical-Pictured below: Neckline falls diagonally-one side strapless the other either with sleeve or sleeveless.
Queen Ann-High neckline curving into a sweetheart around the decolletage area

Sweetheart-Directly above: Plunges into an open heart shape just like a valentine..
Keyhole-Open tear-drop. Strapless-Either cut straight across or sweetheart shaped, the strapless is held up by boning inside the bodice.