perimeter

noun

pe·rim·e·ter | \ pə-ˈri-mə-tər

Definition of perimeter

1a : the boundary of a closed plane figure

b : the length of a perimeter

2 : a line or strip bounding or protecting an area

3 : outer limits —often used in plural

4 : the part of a basketball court outside the three-point line

Synonyms Parameter vs. Perimeter Did You Know? Example Sentences Learn More about perimeter

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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

Did You Know?

The perimeter of a prison is ringed with high walls and watchtowers, and the entire perimeter of Australia is bounded by water. In geometry, you may be asked to calculate the perimeter of various geometrical shapes. In basketball, the perimeter is the area beyond the free-throw circle; a "perimeter player" tends to stay outside that circle. Try not to confuse this word with parameter, which usually means a rule or limit that controls what something is or how it can be done.

Examples of perimeter in a Sentence

He scored from the perimeter. soldiers guarding the perimeter of the camp

Recent Examples on the Web

Dudley, 33, is a 12-year veteran who will help space the court for the Lakers with his perimeter shooting. — Broderick Turner, latimes.com, "Veteran Jared Dudley agrees to minimum deal with the Lakers," 2 July 2019 Washington is a player that would fit on their roster and give them some added size, toughness, and perimeter shooting. — Ira Winderman, sun-sentinel.com, "Groundswell from NBA mock drafts is Kentucky’s P.J. Washington to Heat," 20 June 2019 She was acquired by Minnesota in the offseason to add some perimeter shooting, among other things, to a team in need of it. — Joe Ziemer / Special To The Pioneer Press, Twin Cities, "Lynx ride their defense to win over Mercury," 6 June 2019 Uses his athleticism to score in the lane or from the perimeter. — Dan Loumena, latimes.com, "NBA draft 2019 recap: Pick-by-pick analysis starting with Zion Williamson," 21 June 2019 As law enforcement began to set up a perimeter around the crime scene, Fox and other witnesses were shepherded to the FBI command post a block from El Centro College. — Author: Sharon Grigsby, Anchorage Daily News, "Dallas photographer on encounter with masked gunman: ‘If he walks past me and sees me, he’s going to shoot me’," 18 June 2019 Sheriff’s deputies rushed to the area, set up a perimeter and searched for the suspect with the help of dogs, but the suspect eluded capture, Moses said. — Alex Riggins, San Diego Union-Tribune, "Vista father prevents kidnapping of his 2-year-old child; suspect at large," 18 June 2019 As law enforcement began to set up a perimeter around the crime scene, Fox and other witnesses were shepherded to the FBI command post a block from El Centro College. — Sharon Grigsby, Dallas News, "Photographer Tom Fox on encounter with Dallas gunman: 'He's going to look at me around that corner' and shoot," 17 June 2019 Griffin, meanwhile, is hoping to show teams his value as a defender and a player who can score from the perimeter. — Roy Parry, orlandosentinel.com, "UCF standout B.J. Taylor thrilled to work out for hometown Magic," 15 June 2019

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'perimeter.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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Dictionary Entries near perimeter

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Last Updated

11 Jul 2019

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Time Traveler for perimeter

The first known use of perimeter was in the 15th century

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More Definitions for perimeter

perimeter

noun

English Language Learners Definition of perimeter

: the outside edge of an area or surface

: the total length of the lines that form a shape

basketball : the area on a basketball court that is not close to the basket

See the full definition for perimeter in the English Language Learners Dictionary

perimeter

noun

pe·rim·e·ter | \ pə-ˈri-mə-tər

Kids Definition of perimeter

1 : the whole outer boundary of a figure or area

2 : the length of the boundary of a figure

perimeter

noun

pe·rim·e·ter | \ pə-ˈrim-ət-ər

Medical Definition of perimeter

1a : the boundary of a closed plane figure

b : the length of a perimeter

2 : an instrument for examining the discriminative powers of different parts of the retina often consisting of an adjustable semicircular arm with a fixation point for the eye and variable stations for the visual stimuli