Illustration of micrometer
- micrometer 2
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
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 TableExamples of micrometer in a Sentence
Recent Examples on the Web
ArsTechnica, 9 July 2025
The team then cross-referenced the geographic locations of each patient with measurements of PM2.5 air pollution—particulate matter less than 2.5 micrometers in diameter, or about forty times thinner than the average human hair—sorting each subject into high and low levels of air pollution.
—Ian Randall, MSNBC Newsweek, 2 July 2025
Particles that are less than 10 micrometers and 2.5 micrometers in diameter are called PM10 and PM2.5, respectively.
—Tanya Wildt, Freep.com, 5 July 2025
According to Yale Medicine, the particles can be 10 micrometers, PM 10, or as small as 2.5 micrometers, PM 2.5, and the smaller one poses a lot of health risks.
—Julia Gomez, USA Today, 4 June 2025
See All Example Sentences for micrometer
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Noun
For example, particulate matter 2.5, or PM2.5—which has a diameter of 2.5 micrometers or less—can cause respiratory and heart problems.
—ArsTechnica, 9 July 2025
The team then cross-referenced the geographic locations of each patient with measurements of PM2.5 air pollution—particulate matter less than 2.5 micrometers in diameter, or about forty times thinner than the average human hair—sorting each subject into high and low levels of air pollution.
—Ian Randall, MSNBC Newsweek, 2 July 2025
Particles that are less than 10 micrometers and 2.5 micrometers in diameter are called PM10 and PM2.5, respectively.
—Tanya Wildt, Freep.com, 5 July 2025
According to Yale Medicine, the particles can be 10 micrometers, PM 10, or as small as 2.5 micrometers, PM 2.5, and the smaller one poses a lot of health risks.
—Julia Gomez, USA Today, 4 June 2025
See All Example Sentences for micrometer
Cite this Entry
“Micrometer.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/micrometer. Accessed 21 Jul. 2025.
Copy CitationKids 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
micrometry
noun
-ˈkräm-ə-trē
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
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