micrometer

1 of 2

noun (1)

mi·​crom·​e·​ter mī-ˈkrä-mə-tər 

1

: an instrument used with a telescope or microscope for measuring minute distances

2

: a caliper for making precise measurements that has a spindle moved by a finely threaded screw

Illustration of micrometer

• micrometer 2

micrometer

2 of 2

noun (2)

mi·​cro·​me·​ter ˈmī-krō-ˌmē-tər 

: a unit of length equal to one millionth of a meter

called also micron

see Metric System Table

Examples of micrometer in a Sentence

Recent Examples on the Web

Noun

Particulate matter less than 2.5 micrometers in size, PM2.5, sits at a concentration around 40 micrograms per cubic meter in Stockton, but the 2020 August Complex fires raised that level to more than 70 for multiple days. —Noah Haggerty, Los Angeles Times, 1 Dec. 2024

Remarkably, all of our DNA can fit inside a cell’s nucleus, which is only a few micrometers long. —William A. Haseltine, Forbes, 1 Nov. 2024

For now, the team has only printed tiny samples with a diameter of 3 centimeters, a length of 7 centimeters and a resolution of 15 micrometers, per New Scientist. —Margherita Bassi, Smithsonian Magazine, 19 Nov. 2024

Ultrafine particles are aerosols less than 0.1 micrometers, or 100 nanometers, in diameter — about one-thousandth the width of a human hair. —Discover Magazine, 1 Nov. 2024

Word History

Etymology

Noun (1)

French micromètre, from micr- + -mètre -meter

Noun (2)

International Scientific Vocabulary micr- + meter entry 3

First Known Use

Noun (1)

1670, in the meaning defined at sense 1

Noun (2)

1880, in the meaning defined above

Kids Definition

micrometer

1 of 2 noun

mi·​crom·​e·​ter mī-ˈkräm-ət-ər 

1

: an instrument used with a telescope or microscope for measuring very small distances

2

: micrometer caliper

micrometry

-ˈkräm-ə-trē

noun

micrometer

2 of 2 noun

mi·​cro·​me·​ter ˈmī-krō-ˌmēt-ər 

: a unit of length equal to one millionth of a meter

Medical Definition

micrometer

1 of 2 noun

mi·​crom·​e·​ter mī-ˈkräm-ət-ər 

: an instrument used with a telescope or microscope for measuring minute distances

micrometer

2 of 2 noun

mi·​cro·​me·​ter

variants or chiefly British micrometre

ˈmī-krō-ˌmēt-ər 

: micron