parallelepiped vs parallelepipedon

parallelepiped and parallelepipedon both are nouns.

Word	Noun	Adjective	Verb	Adverb
parallelepiped	Yes	No	No	No
parallelepipedon	Yes	No	No	No

As nouns, parallelepiped and parallelepipedon are synonyms defined as:

parallelepiped and parallelepipedon: a prism whose bases are parallelograms

Other synonyms of parallelepiped include parallelopiped, parallelopipedon.

parallelepiped (noun)	parallelepipedon (noun)
a prism whose bases are parallelograms	a prism whose bases are parallelograms