parallelopiped vs parallelepipedon

parallelopiped and parallelepipedon both are nouns.

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

As nouns, parallelopiped and parallelepipedon are synonyms defined as:

parallelopiped and parallelepipedon: a prism whose bases are parallelograms

Other synonyms of parallelopiped include parallelepiped, parallelopipedon.

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