Cylinder [Area of Effect]
Source: D&D 5.2 SRD Rules Glossary
A Cylinder is an area of effect that extends in straight lines from a point of origin located at the center of the circular top or bottom of the Cylinder. The effect that creates a Cylinder specifies the radius of the Cylinder's base and the Cylinder's height.
A Cylinder's point of origin is included in the area of effect.