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

Printing massive structures Confronted with a tight deadline and a reactor design demanding millimeter-level precision, Kairos Power turned to the ASCC following a recommendation from the Department of Energy’s (DOE) Oak Ridge National Laboratory (ORNL). —Georgina Jedikovska, Interesting Engineering, 5 Dec. 2025

The suspension blends road-car comfort with race-car precision, while ultra-thin carbon fiber body panels (just six-tenths of a millimeter thick in places) help keep weight down to an astonishing 2,110 lb (957 kg). —New Atlas, 3 Dec. 2025

Each shot was exact to the millimeter. —James L. Edwards Iii, New York Times, 3 Dec. 2025

Each specimen is a fraction of a millimeter. —Gillian Stawiszynski, Cincinnati Enquirer, 3 Dec. 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