diameter
noun
di·am·e·ter
dī-ˈa-mə-tər 
1
mathematics
: a chord (see chord entry 3 sense 2) passing through the center of a figure or body
2
mathematics
: the length of a straight line through the center of an object or space
the diameter of a circle
dug a hole nearly four feet in diameter
3
physics
: a unit of enlargement used with a number to indicate magnification by a lens or optical system
an object one millimeter wide magnified 40 diameters appears 40 millimeters wide
Examples of diameter in a Sentence
The dotted line indicates the diameter of the circle.
What is the diameter of the tree trunk?
Dig a hole that's two feet deep and three feet in diameter.
Recent Examples on the Web
The underground pipe is 30 inches in diameter and has been in operation since 1953.
—
Laura Schulte, Journal Sentinel, 15 Nov. 2024
She was surrounded by three-foot diameter paper murals of Disney scenes attached to the wall with sticky putty that left dime-sized oil stains for months.
—Heather M. Jones, Parents, 6 Nov. 2024
And its models say that traffic diversion will increase levels of PM10, particulate matter with a diameter of 10 microns or less that harms the hugs and heart and is commonly emitted from vehicles and construction sites.
—Rachel Uranga, Los Angeles Times, 4 Nov. 2024
The fall is when trees put on the majority of their trunk diameter growth.
—Paul Cappiello, The Courier-Journal, 1 Nov. 2024
See all Example Sentences for diameter 
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Laura Schulte, Journal Sentinel, 15 Nov. 2024
She was surrounded by three-foot diameter paper murals of Disney scenes attached to the wall with sticky putty that left dime-sized oil stains for months.
—Heather M. Jones, Parents, 6 Nov. 2024
And its models say that traffic diversion will increase levels of PM10, particulate matter with a diameter of 10 microns or less that harms the hugs and heart and is commonly emitted from vehicles and construction sites.
—Rachel Uranga, Los Angeles Times, 4 Nov. 2024
The fall is when trees put on the majority of their trunk diameter growth.
—Paul Cappiello, The Courier-Journal, 1 Nov. 2024
See all Example Sentences for diameter
Dictionary Entries Near diameter
Cite this Entry
“Diameter.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/diameter. Accessed 3 Dec. 2024.
Copy CitationKids Definition
diameter
noun
di·am·e·ter
dī-ˈam-ət-ər
1
: a straight line passing through the center of a figure or body
especially
: a line segment through the center of a circle with its ends on the circle's circumference
2
: the length of a diameter
Medical Definition
diameter
noun
di·am·e·ter
dī-ˈam-ət-ər
1
: a unit of magnification for an optical instrument equal to the number of times the linear dimensions of an object are apparently increased
a microscope magnifying 60 diameters
2
: one of the maximal breadths of a part of the body
the transverse diameter of the inlet of the pelvis
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