Q. I can’t find any consensus on this: does “quarter century” require a hyphen? Merriam-Webster’s doesn’t even have the term in its dictionary! (The nerve.) It seems that other online dictionaries do (and they also have a hyphen with “half-century”), but I thought it was odd that I couldn’t find “quarter century” referred to as a noun in either CMOS or MW. Thanks!

A. Although “quarter century” doesn’t appear in CMOS, “quarter hour” turns up at 9.37 without a hyphen. When Merriam-Webster’s doesn’t include a phrase, you can assume that it doesn’t recognize it as a compound, and spelling it open is recommended.