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
Katherine Weaver, Chicago Tribune, 31 July 2025
What the researchers found was alarming: adults inhale about 3,200 larger microplastic particles per day in the range of 10 to 300 micrometers across, and 68,000 tinier particles of 1 to 10 micrometers per day.
—Abhimanyu Ghoshal, New Atlas, 31 July 2025
Research by the microbiologist Lars Dietrich (opens a new tab) of Columbia University has shown that in biofilms just 50 micrometers deep — the equivalent of about 20 to 50 cells — oxygen levels plummet in the interior.
—Carrie Arnold, Quanta Magazine, 21 Apr. 2025
Particles that are less than 10 micrometers and 2.5 micrometers in diameter are called PM10 and PM2.5, respectively.
—Kristi Tanner, Freep.com, 13 July 2025
See All Example Sentences for micrometer
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Noun
For comparison, the width of a human hair is about 80 micrometers.
—Katherine Weaver, Chicago Tribune, 31 July 2025
What the researchers found was alarming: adults inhale about 3,200 larger microplastic particles per day in the range of 10 to 300 micrometers across, and 68,000 tinier particles of 1 to 10 micrometers per day.
—Abhimanyu Ghoshal, New Atlas, 31 July 2025
Research by the microbiologist Lars Dietrich (opens a new tab) of Columbia University has shown that in biofilms just 50 micrometers deep — the equivalent of about 20 to 50 cells — oxygen levels plummet in the interior.
—Carrie Arnold, Quanta Magazine, 21 Apr. 2025
Particles that are less than 10 micrometers and 2.5 micrometers in diameter are called PM10 and PM2.5, respectively.
—Kristi Tanner, Freep.com, 13 July 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 22 Aug. 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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