sender

from WordNet (r) 3.0 (2006)

sender
    n 1: someone who transmits a message; "return to sender" [syn:
         {sender}, {transmitter}]
    2: set used to broadcast radio or tv signals [syn:
       {transmitter}, {sender}]

from The Collaborative International Dictionary of English v.0.48

Sender \Send"er\, n.
   One who sends. --Shak.
   [1913 Webster]