Bible Dictionaries
C Q D

Webster's Dictionary

In radiotelegraphy, the letters signified by the code call formerly used (cf. S O S) by ships in distress, formed by combining the code call C Q (formerly used as a general call for all stations) with D for distress.

Bibliography Information
Webster, Noah. Entry for 'C Q D'. Noah Webster's American Dictionary. https://www.studylight.org/​dictionaries/​eng/​web/​c/c-q-d.html. 1828.