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

The second number relates to the diameter in millimeters of the lens at the larger end of the binoculars. —The New York Times, San Diego Union-Tribune, 15 June 2025

Thanks to all this trimming, the Nike team has been able to make the forefoot air pod three millimeters thicker, which gives a little more energy return over the Victory 2. —Alex Hutchinson, Outside Online, 12 June 2025

Together, the technologies enable the integration of more than 10,000 square millimeters of silicon within a package that can be bigger than 21,000 mm2—a massive area about the size of four and a half credit cards. —IEEE Spectrum, 8 June 2025

The crusts can be anywhere from millimeters to several feet thick. —Jeffrey Kluger, Time, 5 June 2025

Word History

Etymology

French millimètre, from milli- + mètre meter

First Known Use

1797, in the meaning defined above

Rhymes for millimeter

• amphitheater
• centimeter
• centimetre
• decimeter
• ergometer
• expositor
• gasometer
• gravimeter
• hexameter
• manometer
• milliliter
• millimetre

Kids 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

ˈmil-ə-ˌmēt-ər 

: one thousandth of a meter

—abbreviation mm