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

Compression levels Compression socks use a medical unit of measurement, millimeters of mercury (mmHg), to rate their level of pressure. — Bestreviews, Mercury News, 9 July 2026

Earlier study of the region had shown that the spreading in the area occurs at an average rate of a bit over 60 millimeters a year. — John Timmer, ArsTechnica, 8 July 2026

The funding will also support continued commercialization of the millimeter-wave drilling system as Quaise raises additional project-level equity and debt financing. — Neetika Walter, Interesting Engineering, 7 July 2026

Hezbollah denounces the deal as a threat to Lebanese sovereignty, while Israeli leaders vow not to cede ‘a millimeter’ until the group is fully disarmed. — Nabih Bulos, Los Angeles Times, 30 June 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