# parameter

Pronunciation: US say "puh-RAM-uh-tur" /pəˈɹæm.ə.tɚ/; UK say "puh-RAM-i-tuh" /pəˈɹæm.ɪ.tə/

## Noun

1. A characteristic or feature that sets something apart from others.
   - Simple: A feature that makes one thing different from others.
   - _Cost was the deciding parameter that distinguished the two proposals._
   - _Each model differs along several parameters, such as weight and range._
2. An input variable in a function definition that receives an actual value, called an argument, when the function runs.
   - Simple: A named value that a function expects, filled in with a real value when the program runs.
   - _The function declares one parameter for the user's name._
   - _She added a second parameter so the method could accept a date._
3. A value held constant throughout an experiment, equation, or calculation, but changed for other versions of it.
   - Simple: A value that stays the same during one calculation but can be changed for another.
   - _The researchers fixed the pressure as a parameter and varied it only between separate runs._
   - _Each curve corresponds to a different value of the same parameter._
4. A variable that describes a property or characteristic of a system, object, or event, or some aspect of it.
   - Simple: A feature you can measure that tells you how a system or object behaves.
   - _Each physical parameter, such as density or viscosity, helps describe the fluid's behavior._
   - _The satellite reports atmospheric parameters back to the ground station._
5. A variable within a model whose value is learned, or trained, by a machine learning algorithm.
   - Simple: A value inside a model that the computer adjusts as it learns from data.
   - _The network updates every parameter after each batch of training data._
   - _Larger language models contain billions of trained parameters._
6. In statistics, a numerical value describing some feature of an entire population, such as its mean, which is usually unknown and estimated from a sample.
   - Simple: A number that describes a whole group, like its true average.
   - _The true proportion of voters is a parameter the poll tries to estimate._
   - _Confidence intervals give a range of likely values for an unknown parameter._
7. The actual value supplied to a formal parameter when a function is called; an argument.
   - Simple: The real value you pass to a function when you call it.
   - _The script reads the first parameter from the command line._
   - _He forgot to supply the second parameter, so the call failed._
8. In an ellipse or hyperbola, a third proportional to any diameter and its conjugate; in a parabola, a third proportional to any abscissa and its corresponding ordinate.
   - Simple: A special length in curves like the ellipse or parabola, found from two related measurements of the curve.
   - _For this ellipse, the parameter equals the third proportional to the chosen diameter and its conjugate._
   - _Geometers derive the parabola's parameter from an abscissa and its ordinate._
9. The ratio of the three crystallographic axes, which fixes the position of any plane within the crystal.
   - Simple: In crystals, a set of numbers that compares the three main directions and helps place each flat face.
   - _From the parameter, the mineralogist worked out where each face sat._
   - _The crystal's parameter relates the lengths of its three axes._
10. The fundamental ratio between the axis lengths characteristic of a given crystal species.
   - Simple: In crystals, the basic ratio of axis lengths that is typical for one kind of mineral.
   - _Quartz has a parameter distinct from that of calcite._
   - _The parameter serves as a fingerprint for the species._
11. Clipping of uniformizing parameter. — Clipping of uniformizing parameter.
   - Simple: Clipping of uniformizing parameter. A short way to say the same thing.
   - _Fix a parameter t and expand the element as a power series in it._
   - _The order of the element equals its valuation relative to the chosen parameter._

## Origin

This comes from French paramètre, from New Latin parametrum, built from Ancient Greek para- ("beside") and métron ("measure").

Source: DictionaryAI, https://dictionaryai.com/define/parameter (written from Wiktionary data, CC BY-SA 4.0: https://creativecommons.org/licenses/by-sa/4.0/).