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
Under dark skies, a telescope with an aperture of 8 inches (200 millimeters) or more can reveal its tiny bluish disk.
—
Anthony Wood, Space.com, 26 Feb. 2026
In a carousel posted to her Instagram account today, Bündchen sported a 38-millimeter black ceramic and steel timepiece worth $8,350.
—Hannah Malach, InStyle, 26 Feb. 2026
The length of her body is one-fifth of a millimeter.
—Literary Hub, 23 Feb. 2026
Its millimeter wave radar detects and tracks targets through weather.
—Prabhat Ranjan Mishra, Interesting Engineering, 22 Feb. 2026
See All Example Sentences for millimeter
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Anthony Wood, Space.com, 26 Feb. 2026
In a carousel posted to her Instagram account today, Bündchen sported a 38-millimeter black ceramic and steel timepiece worth $8,350.
—Hannah Malach, InStyle, 26 Feb. 2026
The length of her body is one-fifth of a millimeter.
—Literary Hub, 23 Feb. 2026
Its millimeter wave radar detects and tracks targets through weather.
—Prabhat Ranjan Mishra, Interesting Engineering, 22 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 28 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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