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Glite Dictionary
micra

micra

9.9
A very small measure of length equal to one thousandth of a millimetre
  • noun
  • /ˈmaɪkrə/
  • Specialized
translation icon : micra
  • The thickness of the material is about two micra.

Examples

  • Dust particles smaller than ten micra can be inhaled into the lungs.

  • One micra is equal to one millionth of a meter.

  • The scientist observed that the particles were only a few micra in size.

  • Under the microscope, the fibers measured several micra across.

  • The size of Brookesia micra, measuring only a few hundred micra in length, makes it one of the smallest chameleons in the world.

  • Dust particles can be as small as ten micra, making them difficult to see with the naked eye.

  • The scientist used a microscope to measure the thickness of the film in micra.

Synonyms

micron
vsmicra
  • Specialized
15 6.9

A unit of length equal to one millionth of a meter for measuring very small things like dust particles

is the rare plural form of that unit
micrometer
vsmicra
  • Specialized
2 4.8

A unit of length equal to one millionth of a meter

is the rare plural form of that metric term

Surface Forms

micra singular
micrae plural

Morphology

micra = micron (semi-transparent) = micron + a

This is a rare classical plural of micron, so the meaning is straightforward if the base word is known, but the plural ending is not a productive modern English pattern.

Etymology

Micra is the rare plural of micron, from the Greek mikron meaning 'small' and related to the prefix micro- you see in words like 'microphone' and 'microbiology'. So micra means very tiny lengths, each equal to one millionth of a meter, which is why scientists use it for very small measurements.