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:
Earlier research demonstrated that microcombs could produce a single precise millimeter wave frequency.
From Science Daily ● Aug. 24, 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
The cutting-edge 3-nanometer process can fit 250 million to 300 million transistors in one square millimeter of silicon.
From The Wall Street Journal ● Jul. 24, 2026
It all contributes to the most complete officiating picture the World Cup has ever seen, right down to the millimeter.
From The Wall Street Journal ● Jul. 13, 2026
Rather, what we know is encoded in cells called neurons— microscopic electrochemical switching elements, typically a few hundredths of a millimeter across.
From "Cosmos" by Carl Sagan
Their population-weighted coastal averages range from roughly 7 to 10 millimeters per year.
From Science Daily ● Aug. 3, 2026
The United States, the Netherlands, and Italy also have elevated rates, averaging approximately 4 to 5 millimeters per year.
From Science Daily ● Aug. 3, 2026
Clarke’s team has spent the last two years sweating grams, watts, millimeters and pennies from every component, system or process, over and over.
From The Wall Street Journal ● Jun. 20, 2026
The region, made up of mountains surrounded by a desert steppe, receives just over 100 millimeters of annual rainfall, classifying it as an desert.
From Barron's ● Jun. 15, 2026
A typical paramecium, for instance, is about two microns wide, 0.002 millimeters, which is really very small.
From "A Short History of Nearly Everything" by Bill Bryson
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.
