The Collaborative International Dictionary of English v.0.48:

Otto \Ot"to\, n.
   See Attar.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Attar \At"tar\, n. [Per. 'atar perfume, essence, Ar. 'itr, fr.
   'atara to smell sweet. Cf. Otto.]
   A fragrant essential oil; esp., a volatile and highly
   fragrant essential oil obtained from the petals of roses.
   [Also written otto and ottar.]
   [1913 Webster]