Operator · WebGlossary.info

In mathematics, a mapping that acts on elements of a space to produce elements of another space (possibly the same space, sometimes required to be the same space). An operator is also used for denoting the symbol of a mathematical operation, which is related with the meaning of “operator” in computer programming. ← Wikipedia
In programming, constructs which behave generally like functions, but which differ syntactically or semantically from usual functions. Common simple examples include arithmetic (addition with +), comparison (with >), and logical operations (such as AND or &&). More involved examples include assignment (usually = or :=), field access in a record or object (usually .), and the scope resolution operator (often ::). Languages usually define a set of built-in operators, and in some cases allow users to add new meanings to existing operators or even define completely new operators. ← Wikipedia