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.
A certified copy is a copy (often a photocopy) of a primary document, that has on it an endorsement or certificate that it is a true copy of the primary document. It does not certify that the primary document is genuine, only that it is a true copy of the primary document. A certified copy is often used in English-speaking common law countries as a convenient way of providing a copy of documents.