Source : Webster's Revised Unabridged Dictionary (1913)

Twitter \Twit"ter\, v. i. [imp. & p. p. {Twittered}; p. pr. &
   vb. n. {Twittering}.] [OE. twiteren; of imitative origin; cf.
   G. zwitschern, OHG. zwizzir?n, D. kwetteren, Sw. qwitra, Dan.
   quiddre. Cf. {Titter}.]
   1. To make a succession of small, tremulous, intermitted
      noises.

            The swallow twittering from the straw-built shed.
                                                  --Gray.

   2. To make the sound of a half-suppressed laugh; to titter;
      to giggle. --J. Fletcher.

   3. [Perhaps influenced by twitch.] To have a slight trembling
      of the nerves; to be excited or agitated.

Twittering \Twit"ter*ing\, n.
   1. The act of one who, or that which, twitters.

   2. A slight nervous excitement or agitation, such as is
      caused by desire, expectation, or suspense.

            A widow, who had a twittering towards a second
            husband, took a gossiping companion to manage the
            job.                                  --L'Estrange.