rad

1
[ rad ]
See synonyms for rad on Thesaurus.com
nounPhysics.
  1. a unit of absorbed dose of radiation equal to 0.01 gray: not a standard SI unit, the rad is still used, especially in the U.S., but it is increasingly disfavored.

Origin of rad

1
First recorded in 1915–20; r(adiation) a(bsorbed) d(ose)

Other definitions for rad (2 of 4)

rad2
[ rad ]

noun
  1. Informal. a radical, especially a person with extreme views on political and social issues.

adjective,rad·der, rad·dest.
  1. Slang. excellent; wonderful; cool: a high speed, high energy, totally rad racing game.

Origin of rad

2
First recorded in 1820–25 for 1; 1975–80 for 2; shortening of radical

Other definitions for rad (3 of 4)

rad3
[ rad ]

abbreviationMathematics.
  1. radian; radians.

Origin of rad

3
First recorded in 1910–15; shortening

Other definitions for rad. (4 of 4)

rad.

abbreviationMathematics.
  1. radical.

  2. radix.

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2024

How to use rad in a sentence

British Dictionary definitions for rad (1 of 3)

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

Origin of rad

1
C20: shortened from radiation

British Dictionary definitions for rad (2 of 3)

rad2

symbol for
  1. radian

British Dictionary definitions for rad. (3 of 3)

rad.

abbreviation for
  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

Scientific definitions for rad

rad

[ răd ]


  1. 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 © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

Cultural definitions for rad

rad

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

The New Dictionary of Cultural Literacy, Third Edition Copyright © 2005 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.