radians

n. central angle of an arc of any circle that is equal in length to the radius of the same circle (Mathematics)

The radian, in mathematics, is a unit of plane angle, equal to 180/π degrees, or about 57.2958 degrees. It is represented by the symbol "rad" or, more rarely, by the superscript c (for "circular measure"). For example, an angle of 1.2 radians would be written as "1.2 rad" or "1.2c" (the second symbol can be mistaken for a degree: "1.2°").
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Noun
1. 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)
(synonym) rad
(hypernym) angular unit
(part-meronym) milliradian

n. radian, central angle of an arc of any circle that is equal in length to the radius of the same circle (Mathematics)

RADIANTI