What is the X in X-mas?
1650s in geometry, from Modern Latin parameter (1630s), from Greek para- "beside, subsidiary" (see para- (1)) + metron "measure" (see meter (n.2)).
A geometry term until 1920s when it yielded sense of "measurable factor which helps to define a particular system" (1927). Common modern meaning (influenced by perimeter) of "boundary, limit, characteristic factor" is from 1950s. Related: Parametric.
parameter pa·ram·e·ter (pə-rām'ĭ-tər)
One of a set of measurable factors, such as temperature and pressure, that define a system and determine its behavior and are varied in an experiment.
A factor that determines a range of variations; a boundary.
A statistical quantity, such as a mean or standard deviation of a total population, that is calculated from data and describes a characteristic of the population as opposed to a sample from the population.
A psychoanalytic tactic, other than interpretation, used by the analyst to further the patient's progress.
A factor that restricts what is possible or what results. Not in technical use.
A distinguishing characteristic or feature. Not in technical use.
A quantity or number on which some other quantity or number depends. An informal example is, “Depending on the traffic, it takes me between twenty minutes and an hour to drive to work”; here, “traffic” is the parameter that determines the time it takes to get to work. In statistics, a parameter is an unknown characteristic of a population — for example, the number of women in a particular precinct who will vote Democratic.
Note: The term is often mistakenly used to refer to the limits of possible values a variable can have because of confusion with the word perimeter.
in mathematics, a variable for which the range of possible values identifies a collection of distinct cases in a problem. Any equation expressed in terms of parameters is a parametric equation. The general equation of a straight line in slope-intercept form, y=mx+b, in which m and b are parameters, is an example of a parametric equation. When values are assigned to the parameters, such as the slope m=2 and the y-intercept b=3, and substitution is made, the resulting equation, y=2x+3, is that of a specific straight line and is no longer parametric