micrometer

¹ American  

[mahy-krom-i-ter] / maɪˈkrɒm ɪ tər /

especially British, micrometre

noun

1. any of various devices for measuring minute distances, angles, etc., as in connection with a telescope or microscope.

2. Also called micrometer caliper.  Also called mike.  a precision instrument with a spindle moved by a finely threaded screw, for the measurement of thicknesses and short lengths, commonly used by machinists for turning shafts or boring holes.

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micrometer ² American  

[mahy-kroh-mee-ter] / ˈmaɪ kroʊˌmi tər /

noun

1. micron.

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micrometer British  

/ maɪˈkrɒmɪtə, ˌmaɪkrəʊˈmɛtrɪk /

noun

1. any of various instruments or devices for the accurate measurement of distances or angles

2. Also called: micrometer gauge.   micrometer calliper.  a type of gauge for the accurate measurement of small distances, thicknesses, diameters, etc. The gap between its measuring faces is adjusted by a fine screw, the rotation of the screw giving a sensitive measure of the distance moved by the face

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micrometer ¹ Scientific  

/ mī′krō-mē′tər /

1. A unit of length in the metric system equal to one millionth (10 ^{- 6}) of a meter.

2. Also called micron

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micrometer ² Scientific  

/ mī-krŏm′ĭ-tər /

1. A device for measuring very small distances, angles, or objects, especially one based on the rotation of a finely threaded screw, as in relation to a microscope.

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Other Word Forms

• micrometric adjective
• micrometry noun

Etymology

Origin of micrometer¹

First recorded in 1660–70; micro- + -meter

Origin of micrometer²

micro- + meter ¹

Example Sentences

Each sample was carefully filtered to remove anything larger than one micrometer.

From Science Daily • Mar. 29, 2026

The first study, published in the journal TrAC Trends in Analytical Chemistry, looked at both microplastics and nanoplastics, or particles that are less than 1 micrometer long.

From Salon • Jan. 2, 2025

The chip Myny's group made is less than 30 micrometer thick, less than a human hair.

From Science Daily • Apr. 24, 2024

Axons are typically one micrometer in diameter -- several times thinner than a human hair -- making them vulnerable and easily damaged by inflammation, trauma, reduced blood flow to the brain and infection.

From Science Daily • Jan. 31, 2024

Acererak made a final, desperate move to avoid my charge and dropped a micrometer too low.

From "Ready Player One: A Novel" by Ernest Cline