Hyphens, En Dashes, Em Dashes

Q. It’s 2020. Can we please stop using a hyphen in “dropdown”?

A. Yes, if you follow the Microsoft Writing Style Guide. That guide now spells dropdown without a hyphen (as of June 2026). But it also says to use the term only as an adjective (never as a noun) and then only in certain contexts: “Most of the time, avoid talking about UI elements.” Merriam-Webster, meanwhile, lists “drop-down” and “dropdown” as equal variants for the noun form, while showing the adjective as always hyphenated.

[This answer relies on the 18th edition of CMOS (2024) unless otherwise noted.]