A widow's peak is a "V" shape in the middle of the hairline. This term was originally used because this type of hairline was thought to indicate that a woman would outlive her husband. The shape reminded the observer of a style of headdress worn by a woman in mourning. Despite the name, both men and women can have a widow's peak hairline.
Whether you will have a widow's peak hairline is determined by your genes. You may be surprised to learn that widow's peak hair is caused by a dominant gene. You inherit one gene that determines the shape of your hairline from each parent. If one or both copies of them are the widow's peak version, then your hairline has the distinctive "V" shape. However, if you inherit two straight hairline genes from your parents, your hairline will be straight.
If one of your parents has a widow's peak and the other one doesn't, that doesn't necessarily mean that all the children in the family will have a widow's peak hairline. It will depend on whether the parent with the widow's peak inherited two dominant genes or one dominant one and one recessive one.
In a situation where the parent with the widow's peak has two dominant genes, then the children will inherit this characteristic as well. However, if the parent with the widow's peak hairline has a dominant and a recessive gene, and the other parent has two recessive genes, then some of the children may have a straight hairline and some may inherit the widow's peak. In fact the chance that a child will inherit a widow's peak hairline in this situation is 50%.
A number of famous people have a widow's peak. In stories and on film, this trait may be associated with a villain, such as in the case of Count Dracula. You may recall that Eddie Munster, from the television program, "The Munsters," also had this distinctive hairline.
Another villain depicted as having widow's peak hair is The Joker from "Batman" comic books and films. Hannibal Lecter is described as having one in the novels that feature his story.
Actors Keanu Reeves, John Travolta, and Wentworth Miller all have widow peaks. Marilyn Monroe had one, as did Boris Karloff. Mikhail Baryshnikov, the famous Russian dancer, also has one.