or mi·kron


noun, plural mi·crons, mi·cra [mahy-kruh] /ˈmaɪ krə/.

Also called micrometer. the millionth part of a meter. Symbol: μ, mu
Physical Chemistry. a colloidal particle whose diameter is between 0.2 and 10 microns.
Physics. a very small unit of pressure, equal to that exerted by a column of mercury 1μ high.

Origin of micron

1880–85; < Greek mīkrón a little, noun use of neuter singular of mīkrós small; see -on1
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for micron

Contemporary Examples of micron

Historical Examples of micron

  • The man who studies bacteria measures by the micron, 25,000 of which go to the inch.

    Rustic Sounds

    Francis Darwin

  • But with the destruction of the planet an almost certainty, the collective nervous system was just one micron away from explosion.

    Alien Offer

    Al Sevcik

  • This unit is the one-thousandth part of a millimeter and is called the micro-millimeter or micron.

    The Fundamentals of Bacteriology

    Charles Bradfield Morrey

  • Their size is measured by the unit used in the microscope, called the micron, which is about 1⁄25000 of one inch.

British Dictionary definitions for micron


noun plural -crons or -cra (-krə)

a unit of length equal to 10 –6 metre. It is being replaced by the micrometre, the equivalent SI unit

Word Origin for micron

C19: New Latin, from Greek mikros small
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for micron

"one millionth of a meter," 1892, coined 1880 in French from Greek mikron, neuter of mikros "small" (see mica).

Online Etymology Dictionary, © 2010 Douglas Harper

Medicine definitions for micron


n. pl. mi•crons

The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.

Science definitions for micron



See micrometer2.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.