A prismatoid having planar sides and the same number of vertices in both of its parallel planes. The faces of a prismoid are therefore either trapezoids or parallelograms.
Ball and Coxeter (1987) use the term to describe an antiprism.
Prismoid
See also
Antiprism, Prism, PrismatoidExplore with Wolfram|Alpha
References
Ball, W. W. R. and Coxeter, H. S. M. Mathematical Recreations and Essays, 13th ed. New York: Dover, p. 130, 1987.Referenced on Wolfram|Alpha
PrismoidCite this as:
Weisstein, Eric W. "Prismoid." From MathWorld--A Wolfram Web Resource. https://mathworld.wolfram.com/Prismoid.html