Avoid the jargonistic use of this word to mean simply 'something measured or measurable'. One of many dimensions or ways of measuring or describing an object or evaluating a subject: (1) In a mathematic expression, an arbitrary constant that can possess different values (with each value defining other expressions), and can thereby determine the specific form but not the general nature of the expression; e.g., in the equation y = a + bx, a and b are parameters. (2) In statistics, a term used to define a characteristic of a population, in contrast to a sample from that population, e.g., the mean and standard deviation of a total population. (3) In psychoanalysis, any tactic, other than interpretation, used by the analyst to further the patient's progress. [para- + G. metron, measure]