A unibrow (or jacco brow or monobrow; called synophrys in medicine) is a single eyebrow created when the two eyebrows meet in the middle above the bridge of the nose.[1] The hair above the bridge of the nose is usually of the same color and thickness as the eyebrows, giving the appearance that they converge to form one uninterrupted line of hair.
The first known use of the word unibrow was in 1988.[2]
A unibrow is considered as a sign of beauty in Arab culture. Its popularity causes women to draw a black line joining the brows as a part of their routine makeup to fake a unibrow. A study found the prevalence of synophrys to be at 11.87% in the Omani population.[3]
In Tajikistan,[4] a unibrow is viewed as an attractive quality in both men and women.[citation needed] For women, it is associated with virginity and purity and, in men, virility.[citation needed] If there is no unibrow present, or if it is weak, it is commonplace for women to use a kohl liner or a modern kajal pen to simulate a unibrow.[citation needed]
The unibrow has largely been seen as undesirable in the United States and United Kingdom, with the hairs often plucked, shaved, or waxed away.[5][6][7]
The unibrow is a recessive genetic trait.[8] It is associated with the PAX3 gene.[5][9]
A unibrow is part of normal human variation, but can also stem from developmental disorders. A unibrow is a recognized feature of Cornelia De Lange syndrome, a genetic disorder whose main features include moderate to severe learning difficulties, limb abnormalities such as oligodactyly (fewer than normal fingers or toes) and phocomelia (malformed limbs), and facial abnormalities including a long philtrum (the slight depression/line between the nose and mouth).
Other medical conditions associated with a unibrow include:
Cornelia de Lange Syndrome