The Collaborative International Dictionary of English v.0.48:

Transmitter \Trans*mit"ter\, n.
   One who, or that which, transmits; specifically, that portion
   of a telegraphic or telephonic instrument by means of which a
   message is sent; -- opposed to receiver.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

electronic device \electronic device\ n.
   a device depending on the principles of electronics and using
   the manipulation of electron flow for its operation.
   [PJC]

   Note: Numerous electronic devices are in daily use, among
         them the television, radio, computer, robot,
         transmitter, receiver, VCR, CD player, etc.
         [PJC]

WordNet (r) 3.0 (2006):

transmitter
    n 1: someone who transmits a message; "return to sender" [syn:
         sender, transmitter]
    2: any agent (person or animal or microorganism) that carries
       and transmits a disease; "mosquitos are vectors of malaria
       and yellow fever"; "fleas are vectors of the plague"; "aphids
       are transmitters of plant diseases"; "when medical scientists
       talk about vectors they are usually talking about insects"
       [syn: vector, transmitter]
    3: set used to broadcast radio or tv signals [syn:
       transmitter, sender]

Moby Thesaurus II by Grady Ward, 1.0:

67 Moby Thesaurus words for "transmitter":
   AM transmitter, FM transmitter, RT transmitter, TelAutography,
   Teletype, Teletype network, Teletyping, amateur transmitter,
   beacon, call box, closed-circuit telegraphy, code, coin telephone,
   desk telephone, dial telephone, duplex telegraphy, electricity,
   extension, facsimile telegraph, fan marker, interrupter, key,
   microphone, mouthpiece, multiplex telegraphy, news ticker,
   pay station, phone, public telephone, push-button telephone,
   quadruplex telegraphy, radiator, radio beacon, radio range beacon,
   radio transmitter, radiomicrophone, radiosonde,
   railroad telegraphy, receiver, sender, simplex telegraphy,
   single-current telegraphy, sounder, stock ticker,
   submarine telegraphy, telegraphics, telegraphy, telephone,
   telephone booth, telephone engineering, telephone extension,
   telephone mechanics, telephone receiver, telephonics, telephony,
   teleprinter, teletypewriter, teletypewriting, televisor, telex,
   ticker, transceiver, typotelegraph, typotelegraphy,
   video transmitter, wall telephone, wire service