Definition of epicycloid in English:



  • A curve traced by a point on the circumference of a circle rolling on the exterior of another circle.

    • ‘The nephroid is the epicycloid formed by a circle of radius a rolling externally on a fixed circle of radius 2a.’
    • ‘These are the epicycloid, the epitrochoid, the hypocycloid and the hypotrochoid and they are traced by a point P on a circle of radius b which rolls round a fixed circle of radius a.’
    • ‘Galileo defended the ‘epicycloids’ of Copernicus, even though Kepler already had presented a much better theory.’
    • ‘He also investigated caustic curves and in particular he studied these associated curves of the parabola, the logarithmic spiral and epicycloids around 1692.’