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parsec

[pahr-sek] /ˈpɑrˌsɛk/
noun, Astronomy
1.
a unit of distance equal to that required to cause a heliocentric parallax of one second of an arc, equivalent to 206,265 times the distance from the earth to the sun, or 3.26 light-years.
Origin
1910-1915
1910-15; par(allax) + sec(ond)2
Dictionary.com Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2014.
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British Dictionary definitions for parsecs

parsec

/ˈpɑːˌsɛk/
noun
1.
a unit of astronomical distance equal to the distance from earth at which stellar parallax would be 1 second of arc; equivalent to 3.0857 × 1016 m or 3.262 light years
Word Origin
C20: from parallax + second²
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
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Word Origin and History for parsecs

parsec

n.

interstellar distance measure, 1913, from first elements of parallax second. It is the distance at which an object has parallax (viewed from Earth) of one second of arc, or about 3.26 light-years.

Online Etymology Dictionary, © 2010 Douglas Harper
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parsecs in Science
parsec
  (pär'sěk')   
A unit of astronomical length equal to 3.26 light-years. It is based on the distance from Earth at which a star would have a parallax of one second of arc. Its metric equivalent is about 30.8 trillion km (19.1 trillion mi). It is used in measuring distances in interstellar and intergalactic space. The closest star to Earth, Alpha Centauri, is about 1.3 parsecs away. Compare astronomical unit, light-year.

The American Heritage® Science Dictionary
Copyright © 2002. Published by Houghton Mifflin. All rights reserved.
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Related Abbreviations for parsecs

parsec

parallax second
The American Heritage® Abbreviations Dictionary, Third Edition
Copyright © 2005 by Houghton Mifflin Company.
Published by Houghton Mifflin Company. All rights reserved.
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