A macron is a bar placed over a single symbol or character, such as . The symbol
is sometimes used to denote the following operations:
1. The complex conjugate .
2. The mean (a.k.a. arithmetic mean)
of a set of values
.
3. Negation of a logical expression.
4. Infrequently, the adjoint operator.
A bar placed over multiple symbols or characters is called a vinculum.