A polygon whose vertices do not all lie in a plane.
Skew Polygon
See also
Regular Skew Polyhedron, Skew QuadrilateralExplore with Wolfram|Alpha
References
Williams, R. "Skew Polygons (Saddle Polygons)." §2.2 in The Geometrical Foundation of Natural Structure: A Source Book of Design. New York: Dover, p. 34, 1979.Referenced on Wolfram|Alpha
Skew PolygonCite this as:
Weisstein, Eric W. "Skew Polygon." From MathWorld--A Wolfram Web Resource. https://mathworld.wolfram.com/SkewPolygon.html