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

In this, all assemblies and elements are assembled in the design position – exactly as in the drawings, down to one thousandth of a millimeter. —Abhishek Bhardwaj, Interesting Engineering, 15 May 2026

One of the most glaring gaps lies between the infrared and millimeter-wavelength radio observations, but the Probe Far-Infrared Mission for Astrophysics (PRIMA) would fill much of it. —Phil Plait, Scientific American, 15 May 2026

Police said the gun that was dropped was a loaded 9-millimeter handgun. —Nathaniel Percy, Oc Register, 14 May 2026

The distance is measured to within a few millimeters, enabling strong tests of general relativity. —Encyclopedia Britannica, 14 May 2026

Word History

Etymology

French millimètre, from milli- + mètre meter

First Known Use

1797, in the meaning defined above

Rhymes for millimeter

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

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