rad

¹

[rad]

noun

Physics.

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.

rad

²

[rad]

noun

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

adjective

radder, raddest 

1. Slang.,  excellent; wonderful; cool.

   a high speed, high energy, totally rad racing game.

rad

³

[rad]

abbreviation

Mathematics.

1. radian; radians.

rad.

⁴

abbreviation

Mathematics.

1. radical.

2. radix.

rad

¹

/ 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

rad

²

symbol

1. radian

rad.

³

abbreviation

1. radical

2. radius

rad

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.

rad

1. An acronym for r adiation a bsorbed d ose. A unit of energy absorbed from ionizing radiation.

Word History and Origins

Origin of rad¹

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

Origin of rad²

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

Origin of rad³

First recorded in 1910–15; shortening

Word History and Origins

Origin of rad¹

C20: shortened from _radiation

Related Words

• astonishing 
• astounding 
• awesome 
• breathtaking 
• fantastic 
• incredible 
• marvelous 
• outrageous 
• phenomenal 
• remarkable 
• spectacular 
• superb 
• terrific 
• unbelievable