telegraph

Short definition from Wiktionary

Noun

1. 1
   Synonym of telegraphy, any process for transmitting arbitrarily long messages over a long distance using a symbolic code.
2. 2
   The electrical device gradually developed in the early 19th century to transmit messages (telegrams) using Morse code; the entire system used to transmit its messages including overhead lines and transoceanic cables.
3. 3
   A visible or audible cue that indicates to an opponent the action that a character is about to take.

Verb

1. 1
   To use a telegraph, send a message by telegraph.
2. 2
   To clearly communicate to another nonverbally, whether by gesture, a change in attitude, or any other sign, especially unintentionally.