6 letters · 7 points in Scrabble
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)
originEtymology tree Latin radiusbor. English radius Proto-Indo-European *-nós Proto-Italic *-nos Latin -nus Latin -ānus Old French -ainder. Middle English -an English -an English radian From radius + -an.
Etymology from Wiktionary, CC BY-SA 3.0