transmitter

(noun) someone who transmits a message. Synonyms: sender. Example: "Return to sender."

(noun) any agent (person or animal or microorganism) that carries and transmits a disease. Synonyms: vector. Examples: "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."

(noun) set used to broadcast radio or tv signals. Synonyms: sender.