A parameter is a limit. In mathematics a parameter is a constant in an equation, but parameter isn’t just for math anymore: now any system can have parameters that define its operation. You can set parameters for your class debate.
Parameter comes from a combination of the Greek word para-, meaning “beside,” and metron, meaning “measure.” The natural world sets certain parameters, like gravity and time. In court, the law defines the parameters of legal behavior. Parameter and perimeter are similar, but a perimeter is the physical distance around an object, while a parameter can contain or define something either physically or abstractly: before you marry, prepare for the parameters of monogamy.