A line is a filled-in 1D sphere, while two points is a hollow sphere. Generally, the word "sphere" refers to hollow spheres. A 3D filled-in sphere is known as a "ball," and a filled-in 2D sphere is called a "disc." I'm not sure what the general word for a filled-in sphere is.
A line is a filled-in 1D sphere, while two points is a hollow sphere. Generally, the word "sphere" refers to hollow spheres. A 3D filled-in sphere is known as a "ball," and a filled-in 2D sphere is called a "disc." I'm not sure what the general word for a filled-in sphere is.