Copy/Copy that

Copy as in written text for a manuscript, article or an advertisement dates from the late 15th century as does its alternative sense to replicate or imitate. ‘Do you copy?’ means do you understand and originates from US military radio communications from c. 1948 and the reply ‘copy that’ means understood. ‘Do not copy’ is the opposite, meaning that the message or command is not understood and requires further elucidation. Note that 'copy that' does not mean the same thing as 'roger that' because the latter means the message has been received, not necessarily understood. Strictly speaking, 'copy that' is normally used when two stations are talking to one another, and other stations are listening in. The stations listening in confirm 'copy that', meaning that that they have have overhead and understood the communication.