diameter

[ dahy-am-i-ter ]

noun

1. Geometry.
   1. a straight line passing through the center of a circle or sphere and meeting the circumference or surface at each end.
   2. a straight line passing from side to side of any figure or body, through its center.
2. the length of such a line.
3. the width of a circular or cylindrical object.

diameter

/ daɪˈæmɪtə /

noun

1. 1. a straight line connecting the centre of a geometric figure, esp a circle or sphere, with two points on the perimeter or surface
   2. the length of such a line
2. the thickness of something, esp with circular cross section

diameter

/ dī-ăm′ĭ-tər /

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

diameter

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

Word History and Origins

Origin of diameter¹

First recorded in 1350–1400; Middle English diametre, from Old French, from Latin diametros, from Greek diámetros “diagonal, diameter,” from dia- dia- + -metros, derivative of métron meter ¹

Word History and Origins

Origin of diameter¹

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

Example Sentences

I also like a slightly wider tire over the stock rubber, but I usually only get an inch larger diameter tire.

From Popular-Science

For now, the team plans to set the diameter of the cones by hand.

From 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.

From Nautilus

In contrast, a raindrop’s diameter can be 20 to 30 times that size.

From Science News For Students

Those deep sockets can increase the eye’s visual ability without increasing its diameter.

From Science News For Students

Kepler-186f is about 11 percent larger than Earth in diameter, which means it has nearly 25% more surface area.

From The Daily Beast

An array of whittled bamboo sticks, each four millimeters in diameter, makes up the two-room installation.

From The Daily Beast

The doctors discovered the entry wound into the frontal lobe with a diameter about equal to that of a cigarette.

From The Daily Beast

Using a 2-inch (5cm) diameter ring cutter, cut the scallops into straight cylinders; reserve the trim.

From The Daily Beast

Pi is officially defined as the ratio of the circumference of a circle to its diameter.

From The Daily Beast

In cross-section the burrows varied from round (three inches in diameter) to oval (three inches high and four inches wide).

From Project Gutenberg

Reckoning that Neptune is the outermost planet of the solar system, that system would have a diameter of 5,584 millions of miles.

From Project Gutenberg

I think 6½ feet diameter for the fly, and 9½ inches diameter for the small wheel, will give speed enough to the drum.

From Project Gutenberg

The organism is an actively motile spiral thread, about four times the diameter of a red corpuscle in length.

From Project Gutenberg

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.

From Project Gutenberg

Related Words

• width