Noun
An arc of a circle which is equal to the radius, or the angle measured by such an arc.
Source: Webster's dictionaryA molecule rotates about 1 radian per picosecond in a fluid, thus this loss occurs at about 10 11 Hz (in the microwave region). Source: Internet
For example, the quantity torque may be thought of as the cross product of force and distance, suggesting the unit newton metre, or it may be thought of as energy per angle, suggesting the unit joule per radian." Source: Internet
The radian measure of angles is the ratio of the length of a circle's arc subtended by an angle whose vertex is the centre of the circle to some other length. Source: Internet
A second of arc, arcsecond (arcsec), or arc second is of an arcminute, of a degree, of a turn, and (about ) of a radian. Source: Internet
As the ratio of two lengths, the radian is a " pure number " that needs no unit symbol, and in mathematical writing the symbol "rad" is almost always omitted. Source: Internet
History The concept of radian measure, as opposed to the degree of an angle, is normally credited to Roger Cotes in 1714. citation Roger Cotes died in 1716. Source: Internet