millimeter
noun
mil·li·me·ter
ˈmi-lə-ˌmē-tər 
variants
US millimeter
or British millimetre
: a unit of length equal to 1/1000 meter see Metric System Table
Examples of millimeter in a Sentence
Recent Examples on the Web
In astronauts who spent about a year aboard the International Space Station, some areas near the top of the brain moved upward by more than 2 millimeters, while the rest of the brain barely moved.
—
Rachael Seidler, The Conversation, 11 Feb. 2026
This increase in blood pressure can climb as high as 200 millimeters of mercury (mm Hg), particularly during exercises like squats and deadlifts, John Higgins, MD, MBA, a sports cardiologist at UTHealth Houston, told Health.
—Sherri Gordon, Health, 10 Feb. 2026
In grainy eight millimeter footage, a young bride named Yvonne Olsen smiles on the patio, runs down the concrete stairs to the ocean and draws her husband's name in the sand.
—Bryan West, USA Today, 10 Feb. 2026
These common cracks are less than one millimeter in width and can go in any direction; hairline cracks can happen after temperature and humidity fluctuations and as a home settles.
—Jessica Elliott, Dallas Morning News, 10 Feb. 2026
See All Example Sentences for millimeter
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Rachael Seidler, The Conversation, 11 Feb. 2026
This increase in blood pressure can climb as high as 200 millimeters of mercury (mm Hg), particularly during exercises like squats and deadlifts, John Higgins, MD, MBA, a sports cardiologist at UTHealth Houston, told Health.
—Sherri Gordon, Health, 10 Feb. 2026
In grainy eight millimeter footage, a young bride named Yvonne Olsen smiles on the patio, runs down the concrete stairs to the ocean and draws her husband's name in the sand.
—Bryan West, USA Today, 10 Feb. 2026
These common cracks are less than one millimeter in width and can go in any direction; hairline cracks can happen after temperature and humidity fluctuations and as a home settles.
—Jessica Elliott, Dallas Morning News, 10 Feb. 2026
See All Example Sentences for millimeter
Cite this Entry
“Millimeter.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/millimeter. Accessed 15 Feb. 2026.
Copy CitationKids Definition
millimeter
noun
mil·li·me·ter
ˈmil-ə-ˌmēt-ər
: a measure of length equal to ¹⁄₁₀₀₀ meter see metric system table
Medical Definition
millimeter
noun
mil·li·me·ter
variants
or chiefly British millimetre
: one thousandth of a meter
—abbreviation mm
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