an apparatus, system, or process for transmitting messages or signals to a distant place, esp. by means of an electric device consisting essentially of a sending instrument and a distant receiving instrument connected by a conducting wire or other communications channel.

Nautical . an apparatus, usually mechanical, for transmitting and receiving orders between the bridge of a ship and the engine room or some other part of the engineering department.

a telegraphic message.

to transmit or send (a message) by telegraph.

to send a message to (a person) by telegraph.

Informal . to divulge or indicate unwittingly (one's intention, next offensive move, etc.), as to an opponent or to an audience; broadcast

The fighter telegraphed his punch and his opponent was able to parry it. If you act nervous too early in the scene, you'll telegraph the character's guilt.

to send a message by telegraph.