rad

Từ điển WordNet v3.1 - WordNet Dictionary

noun

1. a unit of absorbed ionizing radiation equal to 100 ergs per gram of irradiated material
• Hypernyms:
radioactivity unit
2. the unit of plane angle adopted under the Systeme 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)
• Syn:
radian
• Hypernyms:
angular unit
• Part Meronyms:
milliradian