Vinculum (symbol)

A vinculum is a horizontal line put over a mathematical expression. It shows that it belongs together as a group. (Vinculum is Latin for "chain".)

Examples are:

1. groups of digits repeating forever, for example,

2. fractions

3. radicals (in the following example the quantity  is the radicand, and thus has a vinculum over it):

 Other websites  
MathWorld Vinculum Entry with further (more complicated) examples
Periodic Continued Fraction

Category:Mathematical notation