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

His foundation came from craniofacial surgery, operating on children with complex facial deformities, where millimeters determine whether a child can eat, speak, or smile without pain. —Matthew Kayser, USA Today, 12 Dec. 2025

The researchers report that corrosion is triggered by an invisible film of liquid lead just one micron thick, which accelerates metal loss to a staggering rate of several millimeters per year. —Aman Tripathi, Interesting Engineering, 12 Dec. 2025

Alexandria is home to ancient ruins and historic treasures, but Egypt's second-largest city is especially vulnerable to climate change and rising sea levels, sinking by more than three millimeters every year. —CBS News, 8 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

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