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

According to the report delivered to the council, Santa Ana police fired 215 40-millimeter less-lethal rounds, 59 12-gauge beanbag rounds, and deployed CS chemical agents 35 times between June 9 and June 14, where multiple protests took place around the federal building downtown. —Mona Darwish, Oc Register, 24 Apr. 2026

Early wells there will be drilled conventionally before millimeter-wave systems are introduced on hotter wells. —Neetika Walter, Interesting Engineering, 22 Apr. 2026

For now, a 3-millimeter spider from a remote corner of Spain has earned a place in the scientific record — and on video. —Hanna Wickes, Miami Herald, 15 Apr. 2026

At about 3 millimeters in length, the spider is extremely small, even compared to other members of its family. —Hanna Wickes, Charlotte Observer, 15 Apr. 2026

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