Abbreviations

Q. What if Turabian says to use periods with A.D. and B.C. but CMOS recommends no periods—when Turabian is the guide specified for a thesis?

A. Use the periods. (Was that a trick question?)

[Editor’s note: This question was originally sent to us when the sixth edition of Turabian (1996) was current. Starting with the seventh edition (2007), Turabian has recommended “AD” and “BC,” no periods, in line with Chicago.]

[This answer relies on the 17th edition of CMOS (2017) unless otherwise noted.]