Standard protocol in the US dictates that the tassel be worn on the right side of one's mortarboard at commencement and then, during the ceremony, moved to the left side. Teachers and administrators at commencement place their tassels on the left. It symbolizes one's transition from candidate to graduate.
copy. 1  an imitation, reproduction, or transcript of an original: a copy of a famous painting. 2  one of the various examples or specimens of the same book, engraving, or the like. 3  written matter intended to be reproduced in printed form: The editor sent the copy for the next issue to the printer.
Copy that is a short form answer, meaning only that the listener can clearly hear the message. It has lost all literal meaning from the days when radio communication was rare enough that operators recorded every message (or every message from stations on their network) they happened to hear, in order to relay the message if they subsequently established contact with the intended recipient.