parameter

noun

pa·​ram·​e·​ter pə-ˈra-mə-tər 

1

a

: an arbitrary constant whose value characterizes a member of a system (such as a family of curves)

also : a quantity (such as a mean or variance) that describes a statistical population

b

: an independent variable used to express the coordinates of a variable point and functions of them compare parametric equation

2

: any of a set of physical properties whose values determine the characteristics or behavior of something

parameters of the atmosphere such as temperature, pressure, and density

3

: something represented by a parameter : a characteristic element

broadly : characteristic, element, factor

political dissent as a parameter of modern life

health care is a universal parameter, … a ubiquitous concern across every age, occupation, and class line.

—Wayne Biddle

4

: limit, boundary

—usually used in plural

the parameters of science fiction

The investigation stayed within the parameters set by the court.

parametric

ˌper-ə-ˈme-trik 

ˌpa-rə-

adjective

parametrically

ˌper-ə-ˈme-tri-k(ə-)lē 

ˌpa-rə-

adverb

Did you know?

Parameter vs. Perimeter

It's very easy to confuse parameter with perimeter. Not only do the two words sound the same, they both connote a boundary or limit.

When parameter is used to mean "a boundary or limit," it is usually in its plural form, and often as the object of a preposition such as within or beyond:

Let's face it, managing weight loss or maintenance can be trying enough within the parameters of a daily routine.
Geoff Kerr, Weight Watchers, November 1991

Though candor sometimes encourages Bruno to "stray beyond the parameters of good taste," his interaction with Lydia is always convincingly portrayed as a loving, tender relationship.
Ron Charles, The Washington Post, 8 Feb. 2011

In geometry, perimeter refers to the boundary of a closed plane figure. You might remember calculating perimeters in school. If each side of an equilateral triangle measures 9 feet, then the perimeter of the triangle measures 27 feet. In more general use, perimeter describes an outer stretch, as in "The college president lived in a house on the perimeter of the campus."

Parameter originally had a meaning pertaining to mathematics as well. The dictionary defines it as "an arbitrary constant whose value characterizes a member of a system (as a family of curves); also : a quantity (as a mean or variance) that describes a statistical population" as well as "an independent variable used to express the coordinates of a variable point and functions of them."

Some twentieth-century usage commentators objected to the use of a scientific-sounding word like parameter in general contexts (as in the examples above), especially to mean "a limit or boundary," theorizing that perimeter must have been what the speaker or writer intended.

However, perimeter was not often used in the phrasings that parameter is used in (that is, as the object of within or beyond) until much later. In fact, a word such as bounds or range or confines often serves as a more appropriate equivalent for parameter than the marginal connotations of perimeter:

But a true novel is an extended piece of fiction: Length is clearly one of its parameters.
Anthony Burgess, The New York Times Book Review, 5 Feb. 1984

Shields will then subsume that request in the overall City operating budget that he will recommend to the City Council in mid-March, and the Council will make its final decisions on the parameters of the budget, including any tax increases or cuts, by the end of April.
Nicholas F. Benton, The Falls Church News Press, 6 Jan. 2016

Examples of parameter in a Sentence

Recent Examples on the Web

The Moccamaster can hold brewing temperatures within a variance of 4 degrees Celsius and extract coffee within very tight parameters. —Scott Gilbertson, Wired News, 9 July 2025

The quantum circuit parameters receive adjustments from the classical optimizer, gradient descent, to minimize the loss function output. —Sadhasivam Mohanadas, Forbes.com, 9 July 2025

What were the creative parameters set up for his scene? —Devon Ivie, Vulture, 7 July 2025

Search criteria can be narrowed down to hardiness, height, bloom time, flower color, and other parameters. —Luke Miller, Better Homes & Gardens, 7 July 2025

Word History

Etymology

New Latin, from para- + Greek metron measure — more at measure

First Known Use

1833, in the meaning defined at sense 1a

Rhymes for parameter

• diameter
• pentameter

Kids Definition

parameter

noun

pa·​ram·​e·​ter pə-ˈram-ət-ər 

1

: an independent variable used to express the coordinates of a point

if the coordinates (x, y) of a point are given by the functions x = f(t) and y = g(t) then the parameter is the variable t

2

: any of a set of properties whose values determine the characteristics or behavior of something

parameters of the atmosphere such as temperature, pressure, and density

parametric

ˌpar-ə-ˈme-trik 

adjective