rad has definitions from the field of physics
1
[ noun ] (physics) a unit of absorbed ionizing radiation equal to 100 ergs per gram of irradiated material

Related terms

radioactivity_unit

2
[ noun ] the unit of plane angle adopted under the System International d'Unites; equal to the angle at the center of a circle subtended by an arc equal in length to the radius (approximately 57.295 degrees)

Synonyms

radian

Related terms

angular_unit milliradian

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