Q. I am copyediting an article about a brand of software. The article repeatedly uses the term dialog, but Merriam-Webster prefers the spelling dialogue. However, the software uses dialog in all its documentation. Which spelling does CMOS prefer in this case? Thank you.
A. Merriam-Webster shows dialog as a “less common” variant, which means that it is standard English and may be used according to preference. If you type “dialogue” and then “dialog” into the CMOS Search box, you’ll find that CMOS happens to prefer dialogue in most contexts but makes an exception for dialog box. And in fact, Merriam-Webster has an entry for dialog box (“a window on a computer screen for choosing options or inputting information”). Context is important.