Cylinder is a geometry node. Wikipedia: Cylinder.
X3D Tooltips of interest: Cylinder.
X3D Specification sections of interest: 13 Geometry3D component, 13.2 Concepts and 13.3.3 Cylinder.
X3D Examples Archives of related interest:
This viewpoint slideshow is online at https://www.web3d.org/x3d/content/examples/ConformanceNist/Geometry/Cylinder/viewpointSlideshow.html
Viewpoint image version history at https://sourceforge.net/p/x3d/code/HEAD/tree/www.web3d.org/x3d/content/examples/ConformanceNist/Geometry/Cylinder/_viewpoints