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

Its heel-to-toe drop is 14 millimeters —which is on the high end for On shoes, but contributes to a smooth forward-rolling feel that makes walking or running in these sneakers feel effortless. —Jasmine Gomez, Travel + Leisure, 20 June 2026

The catch is that future networks will rely more heavily on millimeter-wave and sub-THz frequencies, which offer huge bandwidth but are far easier to block than lower-frequency signals. —New Atlas, 19 June 2026

During testing, the robot produced 34 slices ranging from 6 to 16 millimeters thick. —Aamir Khollam, Interesting Engineering, 19 June 2026

Five or six millimeters—about the length of an average adult’s pinky toenail—might not sound like a lot. —Jackie Flynn Mogensen, Scientific American, 18 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