The difference between Orbicular and Spherical

When used as adjectives, orbicular means circular or spherical in shape, whereas spherical means shaped like a sphere.

check bellow for the other definitions of Orbicular and Spherical

Spherical as an adjective (geometry):

Shaped like a sphere.
Spherical as an adjective (geometry):

(no comparative or superlative) Of, or pertaining to, spheres.
Spherical as an adjective (mathematics):

Of a coordinate system, specifying the location of a point in a plane by using a radius and two angles.
Spherical as an adjective (astrology):

Of or relating to the heavenly orbs, or to the sphere or spheres in which, according to ancient astronomy and astrology, they were set.