What does atomic radius and ionic radius really mean to you?

Atomic radius- It is a measure of the size of its atoms, usually the mean or typical distance from the center of the nucleus to the boundary of the surrounding cloud of electrons.
Ionic radius- It is the radius of an atom's ion.

Although neither atoms nor ions have sharp boundaries, they are sometimes treated as if they were hard spheres with radii such that the sum of ionic radii of the cation and anion