The Collaborative International Dictionary of English v.0.48:

Telegram \Tel"e*gram\, n. [Gr. ? far + -gram.]
   A message sent by telegraph; a telegraphic dispatch.
   [1913 Webster]

   Note: "A friend desires us to give notice that he will ask
         leave, at some convenient time, to introduce a new word
         into the vocabulary. It is telegram, instead of
         telegraphic dispatch, or telegraphic communication."
         --Albany [N. Y.] Evening Journal (April 6, 1852).
         [1913 Webster]

WordNet (r) 3.0 (2006):

telegram
    n 1: a message transmitted by telegraph [syn: telegram,
         wire]

Moby Thesaurus II by Grady Ward, 1.0:

26 Moby Thesaurus words for "telegram":
   Teletype, advice, cable, cablegram, communication, communique,
   day letter, dispatch, embassy, express, fast telegram, flash,
   letter, message, night letter, pneumatogram, radio, radiogram,
   release, send a wire, sign off, sign on, telegraph, telex, wire,
   word