IPA: /ˌreɪdioʊˈtɛlɪˌɡræfi/
KK: /reɪdioʊtɛlɪɡræfi/
A method of sending messages over long distances using radio waves instead of wires.
The invention of radiotelegraphy revolutionized communication at sea.
Radiotelegraphy → It is formed from "radio" (from Latin *radius*, meaning ray or beam) and "telegraphy" (from Greek *tele* meaning far and *grapho* meaning to write). The word describes the process of sending written messages over long distances using radio waves.
Think of 'rays' ('radio') being used to 'write' messages over 'far' distances ('telegraphy'). This helps you remember that radiotelegraphy is about sending messages far away using radio signals.