It has been decided that "duocylinder" isn't the best name for the 22 shape (circle cross circle). It has been suggested that we could use "duocircle". It looks like "duo-" has become a general prefix, meaning "shape formed from crossing X with itself". On a related subject, I think we need a name for "crossing" shapes with each other, since "cross" is already the name of a shape. We already have "technical" words for other transformations - "lathing", "extension"/"extrusion", "contrusion" (?).
As Polyhedron Dude mentioned to me privately, there are certain 4d concepts that aren't named yet:
vertical objects:
3d: pole (1d), wall (n-1 = 2d)
4d: pole (1d), [unnamed] (2d), wall (n-1 = 3d)
gaps:
horizontal hole: tunnel
vertical hole: shaft/pit
horizontal chasm: [unnamed]
vertical chasm: [unnamed] (suggestion: "alley")
vertical gully: [unnamed]