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
Quanta Magazine, 6 Apr. 2026
One micrometer is about 1/70th the width of a human hair.
—Prabhat Ranjan Mishra, Interesting Engineering, 5 Apr. 2026
Anything smaller than 1 micrometer is a nanoplastic that must be measured in billionths of a meter.
—Sandee Lamotte, CNN Money, 2 Apr. 2026
The purifier’s air quality sensor only measures PM2.5 contaminants in the air, while the Blueair Blue Signature adds PM1 (particulate matter with a diameter smaller than 1 micron) and PM10 (particulate matter with a diameter of 10 micrometers or less) readings.
—John R. Delaney, PC Magazine, 2 Apr. 2026
See All Example Sentences for micrometer
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Noun
Hyphae are often barely five micrometers wide — about one-tenth the width of a human hair and much narrower than a plant’s root tip.
—Quanta Magazine, 6 Apr. 2026
One micrometer is about 1/70th the width of a human hair.
—Prabhat Ranjan Mishra, Interesting Engineering, 5 Apr. 2026
Anything smaller than 1 micrometer is a nanoplastic that must be measured in billionths of a meter.
—Sandee Lamotte, CNN Money, 2 Apr. 2026
The purifier’s air quality sensor only measures PM2.5 contaminants in the air, while the Blueair Blue Signature adds PM1 (particulate matter with a diameter smaller than 1 micron) and PM10 (particulate matter with a diameter of 10 micrometers or less) readings.
—John R. Delaney, PC Magazine, 2 Apr. 2026
See All Example Sentences for micrometer
Cite this Entry
“Micrometer.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/micrometer. Accessed 7 Apr. 2026.
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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