The Meaning of Rad: What It Is and How To Use It

Do you know the definition of rad? This article will provide you with all of the information you need on the word rad, including its definition, etymology, usage, example sentences, and more!

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What does the word rad mean?

According to The Free Dictionary, Collins English Dictionary and the American Heritage Unabridged Dictionary of the English Language, the word rad is an adjective that is most often used as a slang term to mean cool or awesome. If someone says something is pretty rad, they mean that it is pretty great. This slang word was popularized in the California surfing community. The pronunciation of rad is ræd. Do you do anything in a rad way?

This word can also refer to a unit in physics that is equivalent to an energy absorption per unit mass of 0.01 joule per kilogram of irradiated material. The former unit of 1 rad is equivalent to 100 ergs of energy per gram of material, or 0.01 gray. It is a unit of measurement of the amount of ionizing radiation absorbed from a radioactive source. This word can also be used in photometry to refer to a proposed unit of quantity of light equal to the amount of energy in luminous form. A milliradian is a unit of angular distance that is equal to one thousandth of a radian. A radian is a standard scientific unit used by scientists that measure angles from the center of a circle to refer to an arc equal in length to the radius. You might see it on the internet or in a journal, or in formulas with an integer. 

According to The Free Dictionary, the word rad also has a plethora of different meanings as an acronym. If you do plan to use one of these different definitions for the acronym RAD, ensure that you are providing the reader or listener with the proper context to be able to decipher your intended meaning. This should be standard practice with any acronym that can have more than one definition. When in doubt, use the full form or full meaning of RAD, not the shorthand or abbreviation.

  •  Rules for Archival Description (Canadian rules for organisation of archives)
  •  Radio
  •  Relais d’Accès Au Droit (French legal aid program)
  •  Religious Affairs Directorate (Turkey)
  •  Retiree Activity Day
  •  Resource Availability Determination
  •  Radial (street suffix)
  •  Reconnaissance Automatique de Documents (French: Automatic Document Recognition)
  •  Rite Aide Corporation (stock symbol)
  •  Rational Application Developer (IBM)
  •  Rapid Application Development (software development)
  •  Royal Association for Deaf People (UK)
  •  Revised Acronym Dictionary
  •  Rape Aggression Defense
  •  Remote Administration Device
  •  Retiree Appreciation Day (US DoD)
  •  Recommendation and Approval Document
  •  Réseau Agriculture Durable (French: Sustainable Agriculture Network)
  •  Radical (mathematics)
  •  Relative Average Deviation
  •  Radians (measure of angle)
  •  Remote Access Device
  •  Royal Academy of Dance
  •  Return to Active Duty
  •  Respiratory Assist Device (medical)
  •  Reprogrammable Application Device
  •  Rapid Access Disk
  •  Revised Alternative Dataflow (US Navy)
  •  Russian Analytical Digest (publication)
  •  Reactive Attachment Disorder (sometimes found in abused and/or adopted children)
  •  Radiate/Radiation
  •  Regional Accountable Depot
  •  Random Agile Deinterleaver
  •  Real-time Active Display
  •  Rapid And Disciplined
  •  Rijksarchiefdienst
  •  Remote Access Dialer
  •  Ropeadope (records and radio)
  •  Requirements Analysis and Design
  •  Resource Allocation Display
  •  Release/d from Active Duty
  •  Research and Development
  •  Requirements Allocation Document
  •  Receive Antenna Diversity
  •  Radius
  •  Roentgen Absorbed Dose 
  •  Resource Allocation Decision (various locations)
  •  Reverse Angle Doctorblade (flexographic printing)
  •  Requirements and Architecture Design
  •  Remote Antenna Driver
  •  Race Against Drugs
  •  Right Axis Deviation (electrocardiogram)
  •  Realtime Agent Developer (Open Networks Engineering)
  •  Rainbow Alliance of the Deaf
  •  Return All Data
  •  Robot Alchemic Drive (video game)
  •  Reactive Airway Disease (asthma)
  •  Router Advertisement Defined
  •  Required Availability Date
  •  Random Access Data
  •  Roughneck Airsoft Detachment
  •  Random Access Drive
  •  Rethinking AIDS Day (April 23)
  •  Resource Access Decision
  •  Reported for Active Duty (US DoD)
  •  Reckless and Deadly (Raven Shield and Battlefield 2 gaming clan)
  •  Rational Application Developer
  •  Rapid Application Development
  •  Retain Acquire Develop (marketing)
  •  Recorded Announcement Device (telecommunications)
  •  Radian
  •  Requirements Approval Document (US Air Force)
  •  Read All Day
  •  Research and Academic Development (various schools)
  •  Reservists on Active Duty (US DoD)
  •  Radiation Absorbed Dose (unit of absorbed dose of ionizing radiation equal to an energy of 100 ergs per gram of irradiated material)
  •  Required Award Date (US DoD)
  •  Request for Authority to Develop
  •  Research and Analysis Division (various locations)
  •  Reichsarbeitsdienst (Labor Service of the German Third Reich)
  •  Rural Action for Development
  •  Réseau d’Activités À Distance (French: Remote Network Activities)

Many different languages also contain words that mean rad. You may notice that in this list of translations of rad from Word Sense that some of these words and phrases look and sound a lot like the word rad. These are called cognates, which is when translations look similar, sound similar, and mean something similar. These are usually formed when words have the same root or language of origin.

  •   Nynorsk: kjempebra‎
  •  Romanian: uimitor‎ (masc.), formidabil‎ (masc.)
  •  Czech: skvělý‎, úžasný‎
  •  Mandarin: 了不起‎ (liǎobuqǐ), 不錯‎, 不错‎ (bùcuò), (vulgar) 牛比‎ (niúbǐ), 酷‎ (kù), 酷斃了‎, 酷毙了‎ (kù bì le), 棒‎ (bàng)
  •  Catalan: fantàstic‎
  •  Finnish: mahtava‎
  •  Italian: magnifico‎, splendido‎, fantastico‎
  •  Navajo: nizhóní‎
  •  Korean: 쩐다‎ (jjeonda)
  •  Dutch: indrukwekkend‎
  •  Spanish: tremendo‎, piola‎
  •  Maori: ka wani kē‎
  •  Portuguese: incrível‎
  •  Japanese: すごい‎ (sugoi), 素敵‎ (すてき, suteki), クール‎ (kūru), 素晴らしい‎ (すばらしい, subarashii)
  •  Bengali: ফাটাফাটি‎ (faţafaţi)
  •  Vietnamese: tuyệt vời‎, tuyệt cú mèo‎ (slang)
  •  Bokmål: kjempebra‎
  •  French: magnifique‎, (formally or slang) génial‎, formidable‎
  •  Russian: круто́й‎, клёвый‎, кла́ссный‎, потря́сный‎, (adverb only) здо́рово‎, потряса́ющий‎
  •  Serbo-Croatian: do jaja‎
  •  Armenian: հիանալի‎
  •  Albanian: birinxhi‎
  •  Hungarian: klassz‎, óriási‎
  •  Lithuanian: stulbinantis‎ (masc.), nuostabus‎ (masc.)
  •  Turkish: harika‎, huşu veren‎ (religious), süper‎ (slang)
  •  Polish: super‎, (vulgar) zajebisty (masc.)
  •  German: großartig‎, beeindruckend‎, (slang) toll‎
  •  Ido: impresoza‎

Overall, the word rad means either a unit of energy or radiation dose equivalent, a unit of plane angle between two radii of a circle that cut off on the circumference an arc equal in length to the radius according to the Systeme International d’Unites, or something that is cool. For disambiguation, make sure that you are clear about which category your definition of rad falls under for evaluation. These are important relationships.


  1. RAD – What does RAD stand for? | The Free Dictionary 
  2. rad: meaning, origin, translation | Word Sense