Vinculum is a horizontal line placed above multiple quantities to indicate that they form a unit. Oftentimes, it is the horizontal line drawn as part of a fraction or radical, such as a + b⁄a - b or √ a + b .
It is most commonly used to denote:
A radical √ 123456
Repeating decimals (0. 111 )
The line segment AB joining two points A and B
The complex conjugate z1 + z2
Negation of a logical expression, A ^ B = ! (A ^ B).
“Vinculum.” From Wolfram MathWorld, mathworld.wolfram.com/Vinculum.html.