Definition of radian in English:

radian

noun

Geometry
  • A unit of measurement of angles equal to about 57.3°, equivalent to the angle subtended at the centre of a circle by an arc equal in length to the radius.

    • ‘The sliding displacement between doublets may be found by multiplying the shear angle, in radians, by the interdoublet distance.’
    • ‘The inverse of the radius of the circle equals the curvature in radians / m.’
    • ‘Notice that the formula involves the use of the exponential function, and that the angles must be in radians.’
    • ‘The maximum deviation of the cantilever from horizontal was 0.06 radians, and so no mathematical or mechanical correction for rotation of the cantilever was implemented.’
    • ‘Given that the field oscillates at 60Hz, this gives me a phase angle of 0.4PI radians between samples.’

Pronunciation:

radian

/ˈreɪdɪən/