CQ Definition
sēkyo͝o
noun
Code letters used at the beginning of radio messages intended for all receivers.
American Heritage
Signal given by radio amateurs, inviting others to enter into communication.
Webster's New World
abbreviation
Charge of quarters.
Webster's New World
(Australia) Central Queensland.
Wiktionary
(Canada) Knight of the National Order of Quebec.
Wiktionary
Origin of CQ
Origin unknown
From American Heritage Dictionary of the English Language, 5th Edition