A configuration of two half-lines, or arms, emanating from a point; the angle is said to be subtended by its arms. The angle is measured as a fraction of a full angle equating to 360 degrees or 2π‎ radians; centring a unit circle at the point, the angle’s measure in radians is equal to the length of the arc between the two arms. Angles may also have a positive (anticlockwise) sense or a negative (clockwise) sense. See also acute angle, adjacent angles, complementary angles, conjugate angles, exterior angle, interior angle, obtuse angle, reflex angle, right angle, straight angle, supplementary angles. Compare solid angle.