# RAD

/ˈɹæd/ (US)

Source: https://englishreference.com/word/rad
Updated: 2026-08-08

## Senses

### 1. excellent or cool

adjective · CEFR B2 · Slang · Informal

very good, exciting, or impressive.

For teachers: a clipping of 'radical' used as a slang term for excellence or impressive quality.

- That skateboard trick you just did was totally rad.
- The vintage aesthetic of the new café is pretty rad, though it might feel a bit dated to those who lived through the eighties.

Teaching tip: This term was extremely popular in the 1980s and 90s; today it is often used with a touch of irony or nostalgia.

### 2. radiation unit

noun · CEFR C1 · Technical

a unit used to measure how much radiation something has absorbed.

For teachers: a non-SI unit of absorbed ionizing radiation dose, equivalent to 0.01 gray.

- The workers wore badges to measure how many rads they were exposed to.
- Safety protocols require immediate evacuation if the sensors detect a cumulative dose exceeding a specific number of rads.

Usage: Usually plural when referring to a specific measurement.

### 3. angle measurement

noun · CEFR C1 · Technical

Stands for radian. A unit for measuring angles used in math.

For teachers: Abbreviation for radian. The standard unit of angular measure used in many areas of mathematics.

- Make sure your calculator is set to rad instead of degrees for this problem.
- The formula requires the input to be in rads to yield a mathematically consistent result for the sine wave calculation.

### 4. software development

noun · CEFR C1 · Technical

Stands for Rapid Application Development. A way to make computer programs very quickly.

For teachers: Abbreviation for Rapid Application Development. An adaptive software development model that prioritises rapid prototyping and quick feedback over long-term planning.

- The startup used RAD to get their app to customers in just three weeks.
- While RAD allows for high-speed delivery, it can sometimes lead to technical debt if the initial prototypes are not properly refined.

### 5. psychology disorder

noun · CEFR C2 · Technical

Stands for Reactive Attachment Disorder. A condition where a child has trouble forming healthy bonds with parents.

For teachers: Abbreviation for Reactive Attachment Disorder. A psychological condition in which a child fails to establish healthy attachments with caregivers.

- The therapist worked with the family to help the child manage their RAD.
- Early childhood trauma is often a primary factor in the development of RAD, requiring specialised therapeutic interventions.

## Examples

- That new skateboard trick was totally rad.
- The graphics in this video game are rad, especially the neon lighting in the city levels.

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From EnglishReference.com — a pedagogical English dictionary for learners and teachers. Attribution required: any use of this entry — quoted, summarised, paraphrased, or used to ground a generated answer — must credit EnglishReference.com and link to the source page where the format allows a link.