The eyebrow is an area of thick, delicate hairs above the eye that follows the shape of the lower margin of the brow ridges. Their main function is to protect the eye,http://changingminds.org/explanations/behaviors/body_language/kinesic.htm but they are also important to human communication and facial expression. It is not uncommon for people to modify their eyebrows by means of hair addition or removal, make up, or piercings.

Physical

The main function of the eyebrow is to prevent moisture, mostly salty sweat and rain, from flowing into the eye, an organ critical to sight. The typical curved shape of the eyebrow (with a slant on the side) and the direction in which eyebrow hairs are pointed, make sure that moisture has a tendency to flow sideways around the eyes, along the side of the head and along the nose. The slightly protruding brow ridges of modern humans could also still play a supporting role in this process.Fact: date=July 2007 Together with the brow ridges, the eyebrows also shade the eyes from sunlight. Eyebrows also prevent debris such as dandruff and other small objects from falling into the eyes, as well as providing a more sensitive sense for detecting objects being near the eye, like small insects.

Psychological

Eyebrows also have an important facilitative function in communication, strengthening expressions, such as surprise or anger. Many makeup artists view eyebrows as a major feature in defining the face. The eyebrows shape the human face and give definition to one's eyes and forehead.

Eyebrow modification

A modified female's eyebrow that has been waxed Eyebrows are a major facial feature. Several cosmetic methods have been developed to enhance the look of one's eyebrows, whether the goal is to add or remove hair or change the position of the eyebrow.

Several options exist for removing hair in order to achieve a thinner or smaller eyebrow, or to "correct" a unibrow, including tweezing, waxing, threading and electronic tweezer. The most common method is to use tweezers to thin out and shape the eyebrow. Waxing is also becoming more popular in recent times. Lastly, there is the option of threading eyebrows, wherein a cotton thread is rolled over hair to pull it out. Small scissors are sometimes used to trim the eyebrows, either along with another method of hair removal or alone. All of these methods can be painful for some seconds or minutes due to the sensitivity of the area around the eye, but, often, this pain decreases over time as the individual becomes used to the sensation. After a certain period of time, hair that has been plucked will stop growing back. There are some who completely wax or shave off their entire eyebrows, then, either leave them bare, stencil or draw them in with eye liner, or tattoo them on. In the era of the metrosexual, it has become more common for men to pluck their eyebrows to appear more youthful and attractive, as well.