Why do Harvard degree abbreviations seem to be written backwards?

Some Harvard degree abbreviations appear to be backwards because they follow the tradition of Latin degree names. The undergraduate degrees awarded by Harvard University are the A.B. and S.B. The A.B. is an abbreviation for the Latin name for the bachelor of arts (B.A.) degree "artium baccalaureus." The S.B., Latin for "scientiae baccalaureus," is the bachelor of science (B.S.). Likewise A.M., equivalent to the master of arts (M.A.), is Latin for "artium magister"; and, S.M., equivalent to the master of science (M.S.), is Latin for "scientiae magister."

Harvard does not write all degrees backwards, however. Ph.D. is an abbreviation for the Latin "philosophiae doctor," translated as "doctor of philosophy." M.D., doctor of medicine, stands for the Latin "medicinae doctor." J.D., Latin for "juris doctor" or "jurum doctor," is the doctor of law or doctor of laws, respectively.

Some degrees are too new to have Latin names, though the abbreviations appear to be backwards. In many of these cases, Harvard kept the "reverse" abbreviations because of tradition.