The Collaborative International Dictionary of English v.0.48:

Tobit \To"bit\, n.
   A book of the Apocrypha.
   [1913 Webster]

WordNet (r) 3.0 (2006):

Tobit
    n 1: an Apocryphal book that was a popular novel for several
         centuries [syn: Tobit, Book of Tobit]