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
In April 1970, hailstones measuring 4 inches in diameter slammed into Ripley County, according to data provided by NWS.
—
John Tufts, The Indianapolis Star, 6 May 2024
How about a handle 13 centimeters long and 6 centimeters in diameter?
—Rhett Allain, WIRED, 4 May 2024
See all Example Sentences for diameter 
John Tufts, The Indianapolis Star, 6 May 2024
How about a handle 13 centimeters long and 6 centimeters in diameter?
—Rhett Allain, WIRED, 4 May 2024
See all Example Sentences for diameter
These examples are programmatically compiled from various online sources to illustrate current usage of the word 'diameter.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.
Dictionary Entries Near diameter
Cite this Entry
“Diameter.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/diameter. Accessed 9 May. 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
Love words? Need even more definitions?
Merriam-Webster unabridged
Share