WordNet
n. key consisting of a lever that sends a telegraph signal when it is depressed and the circuit is closed
Wikipedia
Telegraph key is a general term for any switching device used primarily to send Morse code. Similar keys are used for all forms of manual telegraphy, such as in ‘wire’ or electrical telegraph and ‘wireless’ or radio telegraphy.
Usage examples of "telegraph key".
From a pocket Stunted took what was unmistakably ordinary copper wires, a telegraph key and a battery, hooked in series.
Longarm figured Fred Ryan was likely still in Fort Smith that morning, but said he knew how to use a telegraph key, if push came to shove and the Signal Corps would patch him through to a line off the reservation.
Longarm took the small skeletonized telegraph key he'd had in his kit and rested it on the crossbar as he went to work with his jackknife.
He went to the telegraph key and banged away on it, but this time there was no chattering response, no sound at all.
He walked over and tapped out a quick tattoo on the brass telegraph key.
On the edge, in front of a leather-cushioned tilt back chair, there was a telegraph key whose wires angled up and through the ceiling.
Joanna thought of the wireless operator in the Marconi shack, hunched over the telegraph key, tirelessly sending.
He began tapping the telegraph key, which was located at the bottom right corner of the transceiver's face.
The only objects Spud could recognize were the microphone, loudspeaker, and telegraph key.
It had been seventeen years since I had handled a telegraph key—.