## Definitions

### from The American Heritage® Dictionary of the English Language, 4th Edition

• n. A unit of angular measure equal to the angle subtended at the center of a circle by an arc equal in length to the radius of the circle, approximately 57°17ʹ44.6〞. See Table at measurement.

### from Wiktionary, Creative Commons Attribution/Share-Alike License

• n. 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

### from the GNU version of the Collaborative International Dictionary of English

• n. An arc of a circle which is equal to the radius, or the angle measured by such an arc.

### from The Century Dictionary and Cyclopedia

• n. The angle subtended at the center of a circle by an are equal in length to the radius. Also called the unit angle in circular measure. It is equal to 57° 17′ 44″. 80625 nearly.
• n. A unit of angular velocity equivalent, approximately, to 0.15916 revolutions per second, or, strictly, to revolutions per second: in full, radian per second.

• n. 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)

## Etymologies

### from Wiktionary, Creative Commons Attribution/Share-Alike License

From radi(us) + -an

## Examples

• Light en - ergy gathered by the sheaths was relayed by lines called radian draws.

Ilse Witch

• A radian is a measurement used to describe angles.

Francis Shanahan[.com]

• A radian is the equivalent of (a) 2 angular degrees (b) 1/(2) of the angle comprising a full circle (c) the circumference of a unit circle (d) 1 = 4 of the angle comprising a full circle

• When to use "radian" mode in casio scientific calculator fx-85ms.? what is difference between methematics and logic or arthematics? true/false For any two subsets A, B in a vector space [A intersection B] = [A] intersection

Yahoo! Answers: Latest Questions

• One radian of phase, symbolized rad (although you can write out the whole word '' radian ''), is equal to about

• Your symplectic one, though, if it has made an error of one A.U. in its position, will put it one radian ahead or behind in its orbit, but still in its correct orbit.

This "Fix" in the GISS Code « Climate Audit

• You'd have to have a pretty accurate launcher radian to assure the launch elevation was precisely the same as last time.

Did You Know?

• As a result, the radian/degree error was quickly diagnosed and known long before any potential use of these results for policy purposes.

Earth's climate crashes in 2013 « Climate Audit

• Re #19C: I had nothing to do with the radian/degree thing, although they all pretend that.

Roll Over, Preisendorfer « Climate Audit

• Spanner Frew yelled something down to one of the Rovers amidships, and the crewman waved back, moving to tighten a radian draw.

Morgawr