The Collaborative International Dictionary of English v.0.48:

Mahomedan \Ma*hom"ed*an\, Mahometan \Ma*hom"et*an\, n.
   See Mohammedan.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Mohammedan \Mo*ham"med*an\, a. [From Mohammed, fr. Ar.
   muh['a]mmad praiseworthy, highly praised.]
   Of or pertaining to Mohammed, or the religion and
   institutions founded by Mohammed; in the latter sense,
   synonymous with Islamic, the term preferred by Moslems.
   [Written also Mahometan, Mahomedan, Muhammadan, etc.]
   [1913 Webster +PJC]

The Collaborative International Dictionary of English v.0.48:

Mohammedan \Mo*ham"med*an\, n.
   A follower of Mohammed, the founder of Islam (also called
   Islamism or Mohammedanism); an adherent of Islam; one who
   professes Mohammedanism or Islamism; a Muslim; a Moslem; a
   Musselman; -- this term is used mostly by non-Moslems, and
   some Moslems find it offensive. [Written also Muhammadan,
   Mahometan, Mahomedan, etc.]
   [1913 Webster +PJC]