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

Band width Wedding bands come in different widths, usually between 5 to 10 millimeters. —Bestreviews, Chicago Tribune, 5 Feb. 2025

Rogers’s wearables are typically less than a millimeter thick, which is thin enough for many medical applications. —IEEE Spectrum, 3 Feb. 2025

The ripples themselves were only 6 millimeters high and spaced 4 centimeters to 5 centimeters apart, conveying that the movement of small waves formed them. —Jack Knudson, Discover Magazine, 29 Jan. 2025

Slightly thicker than Lululemon’s The Mat at six millimeters high, the Manduka Pro is great for folks wanting extra cushioning for their joints. —Kristin Canning, SELF, 24 Jan. 2025

Word History

Etymology

French millimètre, from milli- + mètre meter

First Known Use

1797, in the meaning defined above

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