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

The patina in some areas is over a millimeter thick. —Theo Burman, MSNBC Newsweek, 12 Sep. 2025

The 42mm models have 374-by-446 screens with 989 square millimeters of display area, and the 46mm ones are 416 by 496 with 1,220mm^2. —PC Magazine, 10 Sep. 2025

Without that access, startups and researchers won’t be able to afford to do relevant work using 300-millimeter wafers and advanced chip-technology nodes. —IEEE Spectrum, 10 Sep. 2025

The latter, which are millimeter-size blobs, are each surrounded by black rings that scientists determined contain iron and phosphate after studying them with Perseverance's toolkit. —Monisha Ravisetti, Space.com, 10 Sep. 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