RADIAN
radian, rad
(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)
Source: WordNet® 3.1
Etymology
Noun
radian (plural radians)
(geometry) In the International System of Units, the derived unit of plane angular measure of angle equal to the angle subtended at the centre of a circle by an arc of its circumference equal in length to the radius of the circle. Symbol: rad
Anagrams
• Adrian, Adrina, Ardian, Darian, ardian
Source: Wiktionary
Ra"di*an, n. Etym: [From Radius.] (Math.)
Definition: An arc of a circle which is equal to the radius, or the angle
measured by such an arc.
Source: Webster’s Unabridged Dictionary 1913 Edition