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

Projectile fragments and metal shavings that have penetrated the tissue as a result of gunshot wounds or accidents may travel a few millimeters during the scan. —Michaela Maya-Mrschtik, Scientific American, 6 Aug. 2025

The difference in those extra millimeters, though, is crucial for patients like DuJuan. —Maggie Menderski, The Courier-Journal, 4 Aug. 2025

But the wind sensitivity of modern-day F1 cars, where every millimeter is designed so carefully with maximum aerodynamic efficiency and performance in mind, means a change in the breeze can have a huge impact. —Luke Smith, New York Times, 2 Aug. 2025

Samsung, however, stuck with the same basic silhouette for versions one through six, shaving off a millimeter here and there with each new generation. —ArsTechnica, 31 July 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