noun
Refers to the now mostly historical service of sending written messages via telegraph. Still understood, but rarely used in daily life.
昔は、急ぎの知らせを電報で送ったものだ。
In the old days, people used to send urgent news by telegram.
Compound of 電 (electric) and 報 (report, news), literally 'electric report'. A straightforward kanji compound coined for the telegraph era.