A widow's peak is a distinct point in the hairline in the center of the forehead. The term widow's peak is from the belief that hair growing to a point on the forehead is an omen of early widowhood. This hair anomaly is a result of a lower-than-usual position of the intersection of the bilateral periorbital fields of hair-growth suppression on the forehead.
http://en.wikipedia.org/wiki/Widow's_peak