Radians are a unit of measurement for angles, where one radian is equal to the angle subtended at the center of a circle by an arc that is equal in length to the radius of the circle. In other words, radians measure how much of a full circle an angle covers.
Related terms
Degrees: Degrees are another unit for measuring angles, where there are 360 degrees in a full circle.
Arc Length: Arc length refers to the distance along an arc or curve, which can be measured in radians or other units.
Angular Velocity: Angular velocity measures how quickly an object rotates around an axis and is usually expressed in radians per second.