The Collaborative International Dictionary of English v.0.48:

Librarian \Li*bra"ri*an\ (l[-i]*br[=a]"r[i^]*an), n. [See
   Library.]
   1. One who has the care or charge of a library.
      [1913 Webster]

   2. One who copies manuscript books. [Obs.] --Broome.
      [1913 Webster]

WordNet (r) 3.0 (2006):

librarian
    n 1: a professional person trained in library science and
         engaged in library services [syn: librarian,
         bibliothec]