the opening at the neck of a garment, esp. of a woman's garment, with reference to its shape or its position on the body: a V-neckline; a high neckline.
The line that connects the two lowest points on the intermediate declines of a head-and-shoulders chart pattern. In an inverted head-and-shoulders formation, the neckline connects the two intermediate tops. If the second shoulder breaks through the neckline, it is an indication of a major price movement in the direction of the breakout.