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

Police recovered 44 spent 9-millimeter shell casings at the scene, according to the affidavit. —Mike Toole, CBS News, 19 Dec. 2025

Quaise Energy is experimenting with millimeter-wave drilling, using high-frequency electromagnetic waves transmitted through waveguides to vaporize rock. —Kaif Shaikh, Interesting Engineering, 18 Dec. 2025

During the grueling, six-hour long double jaw surgery, his top jaw was moved forward 11 millimeters, and his lower jaw was moved back 4 millimeters. —Cara Lynn Shultz, PEOPLE, 17 Dec. 2025

At the heart of this invention are tiny optotactile pixels, which are millimeter-scale cells built with a thin graphite film stretched above a small air cavity. —New Atlas, 15 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