parallelepipedon vs parallelepiped

parallelepipedon and parallelepiped both are nouns.

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

As nouns, parallelepipedon and parallelepiped are synonyms defined as:

parallelepipedon and parallelepiped: a prism whose bases are parallelograms

Other synonyms of parallelepipedon include parallelopiped, parallelopipedon.

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