Curved and flat faces.
a cylinder
cylinder
A cylinder
cylinder
A curved line in 3-dimensional space.
A believe this is a cylinder (like the shape of a can), but there might be others.
a cylinder
A cylinder.
a 3D shape called a cylinder
They are straight lines where two plane faces of the shape meet. The definition is sometimes extended to curved lines where curved (3d) faces meet such as at the base of a cone.
sphere