parameter

Noun

parameter (plural parameters)

1. A value kept constant during an experiment, equation, calculation, or similar, but varied over other versions of the experiment, equation, calculation, etc.
   • As molecular surface-to-surface contacts control both solution phenomena and surface phenomena, it is not surprising that various correlations of cohesion parameters and surface phenomena can be found.2007, Charles M. Hansen, Hansen Solubility Parameters, →ISBN
   • The independent parameters of a system or network over F(z) reflect its structure and determine its structural properties (such as the reducibility of coefficient matrix A and its characteristic polynomial det(λI −A), controllability and observability over F(z), etc.).2012, Kai-Sheng Lu, Rational Function Systems and Electrical Networks with Multi-Parameters, →ISBN
2. A variable that describes a property or characteristic of some system (material, object, event, etc.) or some aspect thereof.
   • Cohesion parameters (solubility parameters) can be used with full theoretical justification to characterize many surfaces ...2007, Charles M. Hansen, Hansen Solubility Parameters: A User's Handbook, Second Edition, CRC Press, →ISBN, page 113
   • To this end, we derive an a posteriori error estimator for the error with respect to the unknown parameter.2012, Wolfgang Desch, Franz Kappel, Karl Kunisch, Control and Estimation of Distributed Parameter Systems: International Conference in Maria Trost (Austria), July 15–21, 2001, Birkhäuser, →ISBN, page...
   1. Any measured quantity of a statistical population that summarises or describes an aspect of the population.
   2. (machine learning) A variable of a model that is trained by a machine learning algorithm.
      • The parameter estimation problem considered in this chapter consists of estimating the unknown parameter, ū [a barred v, actually], given N samples of the observation process.2012, Michael Lemmon, Competitively Inhibited Neural Networks for Adaptive Parameter Estimation, Springer Science & Business Media, →ISBN, page 74
      • Fundamental is the regulation of a for-profit OpenAI. The company initially delayed the launch of its earlier GPT-2, with a mere 1.5bn parameters, because the company fretted over its implications.2020 August 11, “The Guardian view on artificial intelligence's revolution: learning but not as we know it”, in The Guardian
3. An input variable of a function definition, that gets an actual value (argument) at execution time.

   Synonyms:

   formal parameter

4. (broadly) An actual value given to such a formal parameter.

   Synonyms:

   argument, actual parameter

5. A characteristic or feature that distinguishes something from others.

   Synonyms:

   attribute, characteristic, designation, vein, distinctiveness, feature, hallmark, owndom, property, propriety

6. In the ellipse and hyperbola, a third proportional to any diameter and its conjugate, or in the parabola, to any abscissa and the corresponding ordinate.
   • The parameter of the principal axis of a conic section is called the latus rectum.
7. The ratio of the three crystallographic axes which determines the position of any plane.
8. The fundamental axial ratio for a given species.