In geometry, a spherical segment is the solid defined by cutting a sphere or a ball with a pair of parallel planes.It can be thought of as a spherical cap with the top truncated, and so it corresponds to a spherical frustum.
The surface of the spherical segment (excluding the bases) is called spherical zone.
In geometry, a spherical cap or spherical dome is a portion of a sphere or of a ball cut off by a plane. It is also a spherical segment of one base, i.e., bounded by a single plane. If the plane passes through the center of the sphere (forming a great circle), so that the height of the cap is equal to the radius of the sphere, the spherical cap is called a hemisphere.
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