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

Using one rotating magnetic field, the team successfully and precisely guided the microrobot at speeds of up to 4 millimeters per second. —Andrew Paul, Popular Science, 13 Nov. 2025

The females give birth on land to dozens of toadlets, each measuring just a few millimeters long. —Mindy Weisberger, CNN Money, 13 Nov. 2025

Founder Annamaria Brivio has described the 4-inch design as a technical feat, refined millimeter by millimeter for comfort while retaining the sharp verticality that defines the brand. —Maggie Clancy, Footwear News, 12 Nov. 2025

Discovered in 1981, the tiny backbones — just a few millimeters long — had not received much attention historically. —Mrigakshi Dixit, Interesting Engineering, 12 Nov. 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