rad

1 of 3

noun

ˈrad How to pronounce rad (audio)
: a unit of absorbed dose of ionizing radiation equal to an energy of 100 ergs per gram of irradiated material

rad

2 of 3

adjective

slang
: cool sense 7, radical

rad

3 of 3

abbreviation

1
radian
2
radius
3
radix

Examples of rad in a Sentence

Recent Examples on the Web
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
Adjective
California Summer is our first of many scents that will transport you to incredible moments in your life or be a part of rad new ones. — Christopher Edwards, PEOPLE, 4 May 2026 Learn about all the extra rad benefits and become a member yourself at Outside Online Dot Com Slash Pod Plus. — Outside Online, 25 Mar. 2026 Original game director Chris Barrett left Destiny 2 development back in mid-2019 to start developing Marathon, which led to a famously rad 2023 trailer. — Paul Tassi, Forbes.com, 25 Feb. 2026 The newest, rad exhibit at the Petersen Automotive Museum features the cars and culture of the '80s and '90s. — Erica Olsen, CBS News, 24 Jan. 2026 See All Example Sentences for rad

Word History

Etymology

Noun

radiation absorbed dose

First Known Use

Noun

1918, in the meaning defined above

Adjective

1978, in the meaning defined above

Time Traveler
The first known use of rad was in 1918

Rhymes for rad

See All Rhymes for rad

Browse Nearby Words

racy
rad
radar
See all Nearby Words

Cite this Entry

“Rad.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/rad. Accessed 3 Aug. 2026.

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Medical Definition

rad

1 of 2 noun
ˈrad How to pronounce rad (audio)
: a unit of absorbed dose of ionizing radiation equal to an energy of 100 ergs per gram of irradiated material

rad

2 of 2 abbreviation
root
—used in writing prescriptions
Etymology

Abbreviation

Latin radix

More from Merriam-Webster on rad

Nglish: Translation of rad for Spanish Speakers

Britannica.com: Encyclopedia article about rad

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