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• micro
  micro

  adjective

  extremely small.
• micro-
  micro-

  a combining form with the meanings “small” (microcosm; microgamete ), “very small in comparison with others of its kind” (microcassette; microlith ), “too small to be seen by the unaided eye” (microfossil; microorganism ), “dealing with extremely minute organisms, organic structures, or quantities of a substance” (microdissection; microscope ), “localized, restricted in scope or area” (microburst; microhabitat ), “(of a discipline) focusing on a restricted area” (microeconomics ), “containing or dealing with texts that require enlargement to be read” (microfilm; microreader ), “one millionth” (microgram ).
• micro–
  micro–

  A prefix that means: “small” (as in microorganism) or “one millionth” (as in microsecond).

micro

¹ American  

[mahy-kroh] / ˈmaɪ kroʊ /

adjective

1. extremely small.

2. minute in scope or capability.

3. of or relating to microcomputers.

4. of or relating to microeconomics.

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noun

• micros
  plural

1. anything extremely small in scope or capability.

2. a microcomputer.

3. microeconomics.

micro- ² American  

especially before a vowel, micr-.

1. a combining form with the meanings “small” (microcosm; microgamete ), “very small in comparison with others of its kind” (microcassette; microlith ), “too small to be seen by the unaided eye” (microfossil; microorganism ), “dealing with extremely minute organisms, organic structures, or quantities of a substance” (microdissection; microscope ), “localized, restricted in scope or area” (microburst; microhabitat ), “(of a discipline) focusing on a restricted area” (microeconomics ), “containing or dealing with texts that require enlargement to be read” (microfilm; microreader ), “one millionth” (microgram ).

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micro ¹ British  

/ ˈmaɪkrəʊ /

adjective

1. very small

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noun

1. short for microcomputer microlepidoptera microprocessor microwave oven

micro- ² British  

combining form

1. small or minute

   microspore

2. involving the use of a microscope

   micrography

3. indicating a method or instrument for dealing with small quantities

   micrometer

4. (in pathology) indicating abnormal smallness or underdevelopment Compare macro-

   microcephaly

   microcyte

5. μ. denoting 10 ^–6

   microsecond

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micro– Scientific  

1. A prefix that means: “small” (as in microorganism) or “one millionth” (as in microsecond).

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Usage

What does micro- mean? Micro- is a combining form used like a prefix meaning “small.” In units of measurement, micro- means "one millionth." The form micro- is often used in a variety of scientific and technical terms. Micro- comes from Greek mīkrós, meaning “small.” The Latin equivalent of mīkrós is parvus, also meaning “small,” which is the source of terms such as parvovirus, a type of virus with a name that literally means “small poison.” To learn more, check out our entry for parvovirus. What are variants of micro-?When combined with words or word elements that begin with a vowel, micro- becomes micr-, as in micrify, which comes from the Latin equivalent of the form. Want to know more? Read our Words That Use article about micr-.

Other Word Forms

Noun Inflected Forms

• micros
  plural

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Etymology

Origin of micro¹

Independent use of micro-, or shortening of words with this initial element

Origin of micro-²

< Greek: combining form representing mīkrós small

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Explanation

Micro things are so small you can't see them, or reduced to a very small scale. When you study a subject like economics on a micro level, you look at individual markets instead of the whole economy. Most topics can be discussed or studied on a micro level — up close, looking at separate examples — or a macro level, stepping back to view the larger, wider picture. A change in climate is hard to see on the micro level (your state may have had a particularly cold winter), but easier on a macro level (the average temperature may still have increased over the last 100 years). Micro comes from the Greek mikros, "small."

Example Sentences

See Examples For:

micro micro- micros

Though the New York-born filmmaker would have deplored today’s micro attention spans, his work has adapted to the 2020s.

From The Wall Street Journal ● Oct. 12, 2026

The analysis revealed an association between genetic risk for Alzheimer's disease and the frequency of nighttime micro awakenings.

From Science Daily ● Aug. 29, 2026

Instead, “American Doctor” focuses on the micro, giving voice to the doctors and caregivers who traditionally have been spared during armed conflicts, as laid out by the Geneva Conventions.

From Los Angeles Times ● Aug. 21, 2026

"I say it's micro power, so we have to think about what micro power can do," he said.

From Barron's ● Aug. 5, 2026

I stare down onto Sagan, at the trees that look like they belong in the yard of my micro dollhouse village.

From "The Last Cuentista" by Donna Barba Higuera

Also, management targets mid-to-high teens growth in assets under management over the medium-term, driven by micro-, small- and medium-sized enterprises and the mortgage segment.

From The Wall Street Journal ● Apr. 27, 2026

“That’s their worldview, and navigating life as a Black woman, you’re going to experience micro- and macroaggressions,” she says.

From MarketWatch ● Feb. 28, 2026

Yes, they’re cheap and convenient, but like a raccoon that crashes your dinner party, they get into everything: our rivers and oceans, and even our bloodstream, in the form of micro- and nano-plastics.

From Seattle Times ● Apr. 19, 2024

The strong chitosan micro- and nanoscale fibrils are hierarchically branched to provide strength and stability to the agarose film where they are embedded.

From Science Daily ● Dec. 11, 2023

This toy raft, mini-raft, micro- raft, might do for a pond, but not for the Pacific Ocean.

From "Life of Pi" by Yann Martel

"All industries are doing very well from micros up to corporates. I can't think of any industry which this year has problems."

From Reuters ● Nov. 5, 2022

“We use it for our dishes here at the bistro and for our events. They’re clean, they have good taste. I like to have micros with bigger stems and he does that.”

From Washington Times ● Jul. 23, 2022

“Alongside the top-line perspective he held, he was able to still make time for the important micros of life.”

From New York Times ● Dec. 2, 2021

The proliferating micros nip at the heels of established craft brewers and multinational conglomerates alike.

From Seattle Times ● Oct. 12, 2017

For some of the larger micros the long pins may be used directly and a different spreading board employed.

From Directions for Collecting and Preserving Insects by C. V. Riley

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