Mohammedanism vs Muhammadanism

Mohammedanism and Muhammadanism both are nouns.

Word	Noun	Adjective	Verb	Adverb
Mohammedanism	Yes	No	No	No
Muhammadanism	Yes	No	No	No

As nouns, Mohammedanism and Muhammadanism are synonyms defined as:

Mohammedanism and Muhammadanism: the monotheistic religious system of Muslims founded in Arabia in the 7th century and based on the teachings of Muhammad as laid down in the Koran

Other synonyms of Mohammedanism include Islam, Islamism, Muslimism.

Mohammedanism (noun)	Muhammadanism (noun)
the monotheistic religious system of Muslims founded in Arabia in the 7th century and based on the teachings of Muhammad as laid down in the Koran	the monotheistic religious system of Muslims founded in Arabia in the 7th century and based on the teachings of Muhammad as laid down in the Koran