r 1 a 1 d 2 i 1 a 1 n 1
6 letters · 7 points in Scrabble
Meaning
noun 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)
originFrom radius + -an.
Etymology from Wiktionary, CC BY-SA 3.0