radian
/ˈreɪdiən/
noun
- A unit for measuring angles, equal to the angle made at the center of a circle by an arc that is the same length as the circle's radius.
- Many scientific calculators have a mode for working in radians instead of degrees.
- In trigonometry class, we learned that a full circle is equal to 2π radians.
- The angle of 1 radian is about 57.3 degrees.