[ mahy-kruh ]
/ ˈmaɪ krə /


a plural of micron.

Definition for micra (2 of 2)


or mi·kron

[ mahy-kron ]
/ ˈmaɪ krɒn /

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 micra

British Dictionary definitions for micra (1 of 2)

/ (ˈmaɪkrə) /


a plural of micron

British Dictionary definitions for micra (2 of 2)

/ (ˈmaɪkrɒn) /

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

Medicine definitions for micra


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 micra

[ mīkrŏn′ ]

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