millimeter
Americannoun
-
millimeters
plural
Other Word Forms
Derived Forms
Inflected Forms
Nouns
Etymology
Origin of millimeter
First recorded in 1800–10; from French millimètre; see milli-, meter 1
Explanation
A millimeter is a tiny unit of measurement. The thickness of a dime is a little more than a millimeter, and there are a thousand millimeters in a meter. If you're using metric units to measure the length of something, you'll be dealing in meters and variations on meters, including millimeters. Look at a ruler that includes centimeters, the units of metric measurement that are closest in length to inches. The smallest units marked on the ruler are millimeters — there are ten of them in each centimeter. Although the word millimeter sounds like "million," it actually means "thousandth of a meter."
Vocabulary lists containing millimeter
Measurement and Data
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Florida's B.E.S.T. Roots: meter, metr
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Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
See Examples For:
They grow about a centimeter or two a year and by sampling cores at the millimeter scale, the team was able to develop windows of monthly temperature records scattered across the past millennium.
From Barron's ● Aug. 27, 2026
Those optical frequencies can then be converted into multiple high-frequency electromagnetic signals known as millimeter waves.
From Science Daily ● Aug. 24, 2026
"The millimeter and submillimeter radio bands remain almost completely unexplored for SETI, so this is really about opening up a new area of parameter space to search."
From Science Daily ● Jul. 30, 2026
"That has paid off really well for us because there are a lot of people out there that are seeking that 70 millimeter presentation."
From Barron's ● Jul. 26, 2026
I got up extremely quietly, took my things from under the bed, and opened the door one millimeter at a time, so it wouldn’t make any noise.
From "Extremely Loud and Incredibly Close" by Jonathan Safran Foer
The Duo weighs 254 grams, and is 11.3 millimeters thick when closed.
From The Wall Street Journal ● Sep. 10, 2026
Each colony was positioned about 5 millimeters from its nearest neighbor.
From Science Daily ● Sep. 4, 2026
“Combine 2 millimeters of rain with 35 degrees Centigrade—it’s bonkers,” O’Malley said.
From The Wall Street Journal ● Aug. 31, 2026
July’s 6.5 millimeters of rain in England, about 0.25 inches, was the lowest since records began in 1836 and less than half the next driest July—in 1911.
From The Wall Street Journal ● Aug. 31, 2026
The weevil is only about thirty millimeters long, easily overlooked, but it has the makings of a myth.
From "The Lives of a Cell" by Lewis Thomas
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
