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

Blue light penetrates one millimeter to reduce inflammation and bacteria, and helps your body clock. —Beth Landman, The Hollywood Reporter, 4 Dec. 2024

Blood pressure is measured by two numbers, expressed in millimeters of mercury (mm Hg): the systolic (upper or first) number and the diastolic (lower or second) number. —Corey Whelan, Verywell Health, 1 Dec. 2024

The city is sinking at a rate of 1-2 millimeters a year. —Lea Lane, Forbes, 30 Oct. 2024

Chiva, just east of Valencia, received 320 millimeters (12.6 inches) of rain in just over four hours, according to the European Severe Weather Database. —CNN, 30 Oct. 2024

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