Q. Are terms of endearment capped when used as a form of address, for example, in “Bring me my shoes, Precious” or “Turn off the TV, Darling”? I believe this used to be a rule, but with the trend toward “down” styling, most editors perhaps have thrown it out.
A. Chicago’s preferred style has always been to lowercase pet names, but you can’t go wrong unless you’re inconsistent, since the issue is guided by preference rather than rule. For more on the subject, see “Capitalizing Kinship Names and the Like” at CMOS Shop Talk, under the heading “Jobs Titles and Terms of Endearment or Respect.”