micron(redirected from micra)
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. 1 Instrument used for measuring extremely small distances. Typical examples are devices used in astronomical telescopes to measure the apparent diameter of celestial objects and similar devices used in microscopes.
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a fractional unit of length equal to 10-6 m or 10-3 mm. Its symbol is μ. The name “micron” was abolished by a resolution of the Thirteenth General Conference on Weights and Measures (1967); according to GOST (All-Union State Standard) 7663–55 and the rule for formation of the names of fractional units, it is to be called the micrometer (Russian mikrometr).
ii. A unit of linear measurement equal to one millionth (10−6) of a meter. Also called a micrometer.
iii. The amount of pressure exerted by a column of mercury one-micrometer (one millionth of a meter) high under standard conditions. A micron of pressure is equal to .001 mm of mercury.
micronOne micrometer, which is one millionth of a meter or approximately 1/25,000 of an inch. The tiny elements that make up a transistor on a chip are measured in micrometers and nanometers. See process technology.
|Magnified 800 Times|
|This is an 800x magnification of a few bits of RAM from an early Motorola microcontroller. Although the actual size of what you see in this picture would fit on a pinhead, the elements in the devices on this chip are several microns wide, which is quite large by today's standards.|