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
diametral
dī-ˈa-mə-trəl
adjective 
Example Sentences
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 There are hundreds of varieties, with flower size ranging from 1 to 12 inches in diameter, and flower colors that run the gamut from pinks, reds, oranges, yellows, whites and many multi-colored forms. 
Janet B. Carson, Arkansas Online, 4 Sep. 2022 These cute little flowers only grow about 4 inches in diameter, just like 'Spoon' mums. Viveka Neveln, Better Homes & Gardens, 2 Sep. 2022 An exemption permit could be issued for trees under 55 inches in diameter on those properties if no construction is planned within that period. John Hilliard, BostonGlobe.com, 23 Aug. 2022 The device, called a Gesundheit-II, separated out the fine aerosolized droplets measuring 5 micrometers or less in diameter, which can linger in the air and leak through cloth and surgical masks. Gretchen Cuda Kroen, cleveland, 19 Aug. 2022 The crater is 450 meters (1,476 feet) in diameter and 300 meters (984 feet) in depth, per the national park. Abigail Adams, PEOPLE.com, 12 July 2022 It’s made from stainless steel, with a mid-sized 41.5mm diameter and a unidirectional rotating bezel. Matthew Catellier, Forbes, 11 July 2022 The probes were lined with four tiny round electrodes, each just over a millimeter in diameter, that were to deliver continuous electrical impulses to Fisher’s nucleus accumbens. Zachary Siegel, Harper’s Magazine , 17 Aug. 2022 Different bee species prefer different-size holes, some as small as a tenth of an inch in diameter. Lucy Papachristou, WSJ, 15 Aug. 2022 See More
Janet B. Carson, Arkansas Online, 4 Sep. 2022 These cute little flowers only grow about 4 inches in diameter, just like 'Spoon' mums. Viveka Neveln, Better Homes & Gardens, 2 Sep. 2022 An exemption permit could be issued for trees under 55 inches in diameter on those properties if no construction is planned within that period. John Hilliard, BostonGlobe.com, 23 Aug. 2022 The device, called a Gesundheit-II, separated out the fine aerosolized droplets measuring 5 micrometers or less in diameter, which can linger in the air and leak through cloth and surgical masks. Gretchen Cuda Kroen, cleveland, 19 Aug. 2022 The crater is 450 meters (1,476 feet) in diameter and 300 meters (984 feet) in depth, per the national park. Abigail Adams, PEOPLE.com, 12 July 2022 It’s made from stainless steel, with a mid-sized 41.5mm diameter and a unidirectional rotating bezel. Matthew Catellier, Forbes, 11 July 2022 The probes were lined with four tiny round electrodes, each just over a millimeter in diameter, that were to deliver continuous electrical impulses to Fisher’s nucleus accumbens. Zachary Siegel, Harper’s Magazine , 17 Aug. 2022 Different bee species prefer different-size holes, some as small as a tenth of an inch in diameter. Lucy Papachristou, WSJ, 15 Aug. 2022 See More Word History
Etymology
Middle English diametre, from Middle French, from Latin diametros, from Greek, from dia- + metron measure — more at measure
First Known Use
14th century, in the meaning defined at sense 1
Kids Definition
diameter
noun
di·am·e·ter dī-ˈa-mə-tər
1
: a straight line that runs from one side of a figure and passes through the center
Measure the diameter of the circle.
2
: the distance through the center of an object from one side to the other : thickness
the diameter of a tree trunk
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
diameter
noun
as in radius
Synonyms & Similar Words
Relevance
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- self-improvers
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- self-incriminations
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- self-indulgent
- self-indulgently