Abbreviations

Q. What is CMOS’s take on the use of and the defining of acronyms in section and subsection headings?

A. It’s fine to use and define unfamiliar acronyms in headings, but that doesn’t take the place of defining them in the text. The text should make sense even if all the headings and subheadings are removed.

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