diameter

[ dahy-am-i-ter ]

/ daɪˈæm ɪ tər /

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See synonyms for diameter on Thesaurus.com

noun

Geometry.

a straight line passing through the center of a circle or sphere and meeting the circumference or surface at each end.
a straight line passing from side to side of any figure or body, through its center.

the length of such a line.

the width of a circular or cylindrical object.

QUIZ

THINGAMABOB OR THINGUMMY: CAN YOU DISTINGUISH BETWEEN THE US AND UK TERMS IN THIS QUIZ?

Do you know the difference between everyday US and UK terminology? Test yourself with this quiz on words that differ across the Atlantic.

Question 1 of 7

In the UK, COTTON CANDY is more commonly known as…

candystring

candyfloss

candypuff

TAKE THE QUIZ TO FIND OUT

Origin of diameter

1350–1400; Middle English diametre<Old French <Latin diametros<Greek diámetros diagonal, diameter, equivalent to dia-dia- + -metros, derivative of métronmeter¹

WORDS THAT MAY BE CONFUSED WITH diameter

circumference, diameter , radius, tangent

Words nearby diameter

diamagnetism, diamanté, diamantiferous, Diamantina, diamantine, diameter, diametral, diametric, diametrical, diametrically, diamide

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

How to use diameter in a sentence

I also like a slightly wider tire over the stock rubber, but I usually only get an inch larger diameter tire.
Six ways to make your ATV even more rugged|By Tyler Freel/Outdoor Life|September 17, 2020|Popular-Science
For now, the team plans to set the diameter of the cones by hand.
How special relativity can help AI predict the future|Will Heaven|August 28, 2020|MIT Technology Review
Both are tiny—Phobos, the larger, is 14 miles in diameter, scarcely bigger than Manhattan Island—but they also circle extremely close to the planet.
These Images Expose the Dark Side of the Solar System - Issue 89: The Dark Side|Corey S. Powell|August 26, 2020|Nautilus
In contrast, a raindrop’s diameter can be 20 to 30 times that size.
Explainer: Rainbows, fogbows and their eerie cousins|Matthew Cappucci|May 1, 2020|Science News For Students

Those deep sockets can increase the eye’s visual ability without increasing its diameter.
This dinosaur was no bigger than a hummingbird|Carolyn Gramling|April 13, 2020|Science News For Students
Kepler-186f is about 11 percent larger than Earth in diameter, which means it has nearly 25% more surface area.
What Does the Discovery of “Another Earth” Mean for Us?|Matthew R. Francis|April 18, 2014|DAILY BEAST
An array of whittled bamboo sticks, each four millimeters in diameter, makes up the two-room installation.
The Royal Academy Wants You to Finish This Artwork|Chloë Ashby|January 24, 2014|DAILY BEAST
The doctors discovered the entry wound into the frontal lobe with a diameter about equal to that of a cigarette.
The Little Syrian Girl With a Bullet in Her Head|Gregory Beals|November 29, 2013|DAILY BEAST
Using a 2-inch (5cm) diameter ring cutter, cut the scallops into straight cylinders; reserve the trim.
Daniel Boulud Reveals His 4 Favorite Recipes From His New Cookbook|Daniel Boulud|October 15, 2013|DAILY BEAST
Pi is officially defined as the ratio of the circumference of a circle to its diameter.
17 Facts to Crack the Mystery of Pi|Abby Haglage|March 14, 2013|DAILY BEAST
In cross-section the burrows varied from round (three inches in diameter) to oval (three inches high and four inches wide).
Summer Birds From the Yucatan Peninsula|Erwin E. Klaas
Reckoning that Neptune is the outermost planet of the solar system, that system would have a diameter of 5,584 millions of miles.
God and my Neighbour|Robert Blatchford
I think 6½ feet diameter for the fly, and 9½ inches diameter for the small wheel, will give speed enough to the drum.
Life of Richard Trevithick, Volume II (of 2)|Francis Trevithick
The organism is an actively motile spiral thread, about four times the diameter of a red corpuscle in length.
A Manual of Clinical Diagnosis|James Campbell Todd
The care shown in rearing insures a perfect straightness of stem, and an equable diameter of about an inch or an inch and a half.
Tobacco; Its History, Varieties, Culture, Manufacture and Commerce|E. R. Billings.

British Dictionary definitions for diameter

diameter

/ (daɪˈæmɪtə) /

noun

a straight line connecting the centre of a geometric figure, esp a circle or sphere, with two points on the perimeter or surface
the length of such a line

the thickness of something, esp with circular cross section

Word Origin for diameter

C14: from Medieval Latin diametrus, variant of Latin diametros, from Greek: diameter, diagonal, from dia- + metron measure

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Scientific definitions for diameter

diameter

[ dī-ăm′ĭ-tər ]

A straight line segment that passes through the center of a circle or sphere from one side to the other.

The length of such a line segment.

Cultural definitions for diameter

diameter

[ (deye-am-uh-tuhr) ]

A straight line passing through the center of a figure, especially a circle or sphere, and joining two opposite points on its circumference.

diameter

Origin of diameter

WORDS THAT MAY BE CONFUSED WITH diameter

Words nearby diameter

Words related to diameter

How to use diameter in a sentence

British Dictionary definitions for diameter

Word Origin for diameter

Scientific definitions for diameter

Cultural definitions for diameter