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.
Historically, the term system operator applied to operators of any computer system, especially a mainframe computer. In general, a sysop is a person who oversees the operation of a server, typically in a large computer system. Usage of the term became popular in the late 1980s and 1990s, originally in reference to BBS operators.