millimeter
Americannoun
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:
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
For example, lowering the pickup’s roof by a single millimeter saved the equivalent of $1.30 in battery cost.
From The Wall Street Journal ● Jun. 20, 2026
While a single 300 millimeter silicon wafer normally produces a few dozen chips, Cerebras uses the entire wafer for one chip, about the size of a dinner plate.
From Barron's ● May 15, 2026
In this environment, the sediment layer grows at a rate of just one thousandth of a millimeter per year.
From Science Daily ● Feb. 2, 2026
She said, “It doesn’t feel small to me,” and I thought about moving a single grain of sand one millimeter.
From "Extremely Loud and Incredibly Close" by Jonathan Safran Foer
The simulations suggest that a detector of this size could achieve spatial resolution of a few millimeters, placing it on par with state-of-the-art plastic scintillator detectors.
From Science Daily ● Jul. 17, 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
The new PCs will be as slim as 14 millimeters thick, and the lightest will weigh less than 3 pounds.
From The Wall Street Journal ● Jun. 1, 2026
According to the new study, published in Science Advances, global sea levels have risen at an average rate of 2.06 millimeters per year since 1960.
From Science Daily ● May 22, 2026
The film itself, loaded into the T-50 by specially trained technicians, was barely wider than the lens—a mere five millimeters.
From "Spies: The Secret Showdown Between America and Russia" by Marc Favreau
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.
