Necklines can be grouped into categories according to their shape and where they cut across the body:

• polo necks (circular)

wrap around the neck itself. Also called turtlenecks:sweater or jersey with a high close-fitting colar.

• jewel necklines (circular)

pass around the base of the neck on all sides. Also called the T-shirt neckline.

• scoop necklines (curved, concave up)

have a curved U shape, where the arms of the U pass over the shoulders. Scoop necklines can be demure or plunging, depending on the depth of the U.

• boat necklines (one edge, nearly linear)

are necklines with a broad opening, but which pass nearly horizontally across the figure near the collarbones. Also called bateau necklines or Sabrina necklines.

• off-the-shoulder necklines (one edge, nearly linear)

are similar to boat necklines in that they generally cut across the figure nearly horizontally, but significantly lower, below the shoulders and collar bone. Such neckline usually pass over the arms but, in the strapless neckline, may pass under the arms. These necklines accentuate the shoulders and neck of the wearer.

• one-shoulder necklines (one edge, nearly linear)

asymmetrical linear necklines that cut across the torso diagonally, usually from one shoulder to under the other arm.

• halter necklines (linear, side edges converge on neck)

feature a high neck with deep, raglan-type armholes or else two straps from the bodice that meet at the back of the neck. In both cases, they form diagonal lines that converge inwards to the neck from the sides. Although such necklines reveal a lot of shoulder, their convergence makes the shoulders seem smaller. Halter necklines can have a horizontal bottom edge, or their two side edges can meet in a V.

• V necklines (2-4 linear edges, side edges diverge)

are formed by two diagonal lines from the shoulder that meet on the chest. These necklines can be demure or plunging, depending on the depth of the V. The surplice version of this neckline (known as a portrait neckline) is an alternative. The V may also be truncated by a small bottom edge, forming a trapezoid.

• Deep neck

Deep necks are low necklines, maybe in either V shape or U shape.

• square necklines (linear side edges neither converge nor diverge)

are characterized by three linear edges, the bottom edge meeting the side edges at right angles. The bottom edge cuts across the figure horizontally and the side edges pass over the shoulders. A special case of this is the slot neckline, in which the side edges are very close (roughly the width of the collar-bone points), forming a narrow slot.

• sweetheart necklines (side edges linear, curved bottom edge concave down)

has a curved bottom edge that is concave down and usually doubly scalloped to resemble the top half of a heart. The side edges often converge on the neck, similar to halter necklines. Sweetheart necklines are good for accentuating the bosom.

• keyhole necklines

are extremely similar to halter necklines, but the converging diagonal lines meet in front of the neck, forming a "keyhole". More generally, a neckline that features a central hole, usually just below the collar bones. These necklines are seen infrequently.