You Could Look It Up

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 “secondary variant,” which means that it is standard English and may be used according to preference. Typing dialogue into the CMOS Search box, I see that CMOS happens to use that form 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.