Definition of diameter
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
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Merriam-Webster unabridged
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Time Traveler for diameter
The first known use of diameter was in the 14th century
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