Radio telegraphy is often associated with Morse code, which was historically used to transmit messages over long distances via electromagnetic waves. However, there are several synonyms for this term, including "wireless telegraphy," "spark-gap telegraphy," and "radio-telegraphy." Each of these terms refers to the use of radio waves to send and receive messages, but they may have slightly different connotations or historical contexts. For example, "wireless telegraphy" is a more general term that encompasses any type of radio communication, while "spark-gap telegraphy" specifically refers to the early days of radio communication when spark gaps were used to generate the electromagnetic waves.