noun
A telegram marked for priority delivery. This term is now largely historical, as telegrams have been replaced by modern communication methods.
昔は、至急電報を打つとすぐに相手に届いた。
In the old days, if you sent an urgent telegram, it would reach the recipient right away.
電報 is a general telegram, while 至急電報 specifically refers to an urgent one.
Compound of 至急 (urgent) and 電報 (telegram).