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rad1

[rad] /ræd/
noun, Physics.
1.
a standard unit of absorbed dose of radiation equal to 0.01 gray2 .
Compare dose (def 4a).
Origin
1915-1920
1915-20; shortened form of radiation

rad2

[rad] /ræd/
noun
1.
Informal. radical.
adjective
2.
Slang. fine; wonderful.
Origin
by shortening of radical

rad

Mathematics
1.
radian; radians.

rad.

Mathematics
1.
2.
Dictionary.com Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2014.
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British Dictionary definitions for rad

rad1

/ræd/
noun
1.
a former unit of absorbed ionizing radiation dose equivalent to an energy absorption per unit mass of 0.01 joule per kilogram of irradiated material. 1 rad is equivalent to 0.01 gray
Word Origin
C20: shortened from radiation

rad2

symbol
1.
radian

rad.

abbreviation
1.
radical
2.
radius
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 rad

"x-ray dose unit," 1918, shortened form of radiation (q.v.). As shortened form of radical (n.), it is attested in political slang from 1820. Teen slang sense of "extraordinary, wonderful" is from late 1970s (see radical (adj.)).

Online Etymology Dictionary, © 2010 Douglas Harper
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rad in Medicine

rad 1 (rād)
n.
A unit of energy absorbed from ionizing radiation, equal to 100 ergs per gram or 0.01 joule per kilogram of irradiated material.

rad 2
abbr.
radian

The American Heritage® Stedman's Medical Dictionary
Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
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rad in Science
rad
  (rād)   
A unit used to measure energy absorbed by a material from radiation. One rad is equal to 100 ergs per gram of material. Many scientists now measure this energy in grays rather than in rads.
The American Heritage® Science Dictionary
Copyright © 2002. Published by Houghton Mifflin. All rights reserved.
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rad in Culture

rad definition


An acronym for radiation absorbed dose. A unit of energy absorbed from ionizing radiation.

The American Heritage® New Dictionary of Cultural Literacy, Third Edition
Copyright © 2005 by Houghton Mifflin Company.
Published by Houghton Mifflin Company. All rights reserved.
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Slang definitions & phrases for rad

rad

adjective

Extraordinary; wonderful; awesome, chill, gnarly: Want to go to this way rad party? (late 1970s+ Teenagers)

noun

A radical (1820+)


The Dictionary of American Slang, Fourth Edition by Barbara Ann Kipfer, PhD. and Robert L. Chapman, Ph.D.
Copyright (C) 2007 by HarperCollins Publishers.
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rad in Technology
The Free On-line Dictionary of Computing, © Denis Howe 2010 http://foldoc.org
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Related Abbreviations for rad

rad

  1. radian
  2. radiation absorbed dose
  3. Slang radical (that is, excellent)

RAD

Royal Academy of Dancing

rad.

  1. radical
  2. radius
  3. radix
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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Encyclopedia Article for rad

the unit of absorbed dose of ionizing radiation, defined in 1962 by the International Commission on Radiological Units and Measurements as equal to the amount of radiation that releases an energy of 100 ergs per gram of matter. One rad is equal approximately to the absorbed dose delivered when soft tissue is exposed to one roentgen of medium-voltage radiation. "Rad" is derived from "radiation absorbed dose." In 1975 it was replaced by the gray (Gy), equal to 100 rads, in the International System of Units (SI). The rad is used now only in the United States.

Learn more about rad with a free trial on Britannica.com
Encyclopedia Britannica, 2008. Encyclopedia Britannica Online.
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4
4
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