A hypocycloid is a type of curve traced by a point on a smaller circle rolling inside a larger stationary circle. The path created depends on the ratio of the radii of the two circles. For example, if the radius of the smaller circle is half that of the larger circle, the hypocycloid will have four cusps, creating a star-like shape. Hypocycloids are a specific case of hypotrochoids, which involve a point on a circle rolling inside another circle. These curves have applications in various fields, including mathematics, engineering, and art, often used to create intricate designs and patterns.