Operator

In Mathematics, an operator is a symbol indicating an operation to be performed on an operand.

The elementary [arithmetic operator]?s

1. addition symbolized by '+'
2. subtraction? symbolized by '-'
3. multiplication? symbolized by '*' or by simple juxtaposition.
4. division? symbolized by '/', '÷' or a horizontal line separating numerator? from denominator?
5. exponentiation (repeated multiplication) by elevation of the number of factors above the base line

are quite standard.

Different branches of mathematics may extend the definitions of operators to represent analogous operations.

1. + has been extended to cover addition of sets?, vectors and matrices.
2. Multiplication of a vector by a particular matrix is a unary operator or transformation; it is common, and only a slight abuse of language, to say the matrix is the operator.