OPOSSUMS ARE MARSUPIALS. If you open just about any field guide to North American mammals, the opossum will probably be the very first of the 380 or so mammal species described. That's because opossums are our only marsupial, and marsupials are considered very ancient forms of mammals.
operator - an agent that operates some apparatus or machine; the operator of the switchboard. manipulator. causal agency, causal agent, cause - any entity that produces an effect or is responsible for events or results. company operator - an operator who works for a company. driver - the operator of a motor vehicle.
A search operator (sometimes referred to as a search parameter) is a character or string of characters used in a search engine query to narrow the focus of the search. In mathematics and computer science, operators are characters or sequences of characters that represent an action or cause an action to be performed.