cylinder-plane intersection

A cylindric section is the intersection of a plane with a right circular cylinder. It is a circle (if the plane is at a right angle to the axis), an ellipse, or, if the plane is parallel to the axis, a single line (if the plane is tangent to the cylinder), pair of parallel lines bounding an infinite rectangle (if the plane cuts the cylinder), or no intersection at all (if the plane misses the cylinder entirely, pp. 7-8).

conic section | cross section | cylinder | cylindrical segment | cylindrical wedge | ellipse | ellipsoidal section | spheric section | spheroidal section | toric section