I do a lot of copy editing for publications that follow Los Angeles Times style, which is just a slight variation on AP style. More recently, I’ve begun copy editing publications that follow the Chicago Manual of Style.
AP says not to use the serial comma, or Oxford comma: “The flag is red, white and blue.”
Chicago (and most English teachers) say to use it: “The flag is red, white, and blue.” That difference tests my attentiveness on a daily basis. But it’s the little things—the curve balls—that are most likely to give me an aneurysm. Here are some terms that have come up in both my AP-style client's work and in my Chicago-style client's work:
shower head/showerheadAP’s default dictionary, “Webster’s New World College Dictionary,” says it’s two words. Chicago’s default dictionary, “Merriam-Webster” says it’s one.
health care/healthcareWhen I’m copy editing for my magazine client, I have to remember to use “health care." For the newspapers, it’s “healthcare.” Again, that’s because of their fallback dictionaries. Merriam-Webster says it’s two words. Webster’s New World has “healthcare” as one.
nightlife/night lifeIn Chicago it's one word. In AP it's two.
And don't even get me started on underway and under way.