operator

1. Person or device that makes another device function or functional. A semiconductor in a circuit-board is an operator which allows the circuit-board to function for example.

2. A specific mathematical function denoted by a symbol. For example, mathematical operators like the plus symbol (+) or minus symbol (-) show what to do to pieces of data.

3. In telecommunications, an operator is a person that one would call for information, to connect to an intended phone number, or when encountering difficulties in connecting to the intended party.