The term CQD Successor is a reference to the international maritime distress signal CQD, which was used from 1904 to 1906. Its successor was the SOS signal, which was adopted in 1906 and is still used today. The crossword solutions for this term are EDEN (4 letters) and SOS (3 letters). EDEN is an acronym for the Emergency Distress Network, which was established in the early 1900s to provide a more efficient way of responding to distress signals. SOS stands for Save Our Souls, which is the phrase associated with the international distress signal.