You may have noticed in some of my previous entries I have used the noun best sellers (“my mother’s collection of best sellers from the ’40s and ’50s”). Not bestsellers. Nor best-sellers. Best seller, a noun, is an open compound, friends, and frankly I’m tired of seeing it misused. Misspelled, actually. (Best-selling, on the other hand, an adjective, correctly uses the hyphen.)

There are three types of compounds: open (high school, vice president), closed (toothache, redhead), and hyphenated (mass-produced, computer-literate). As language lives and grows, compounds that were once open (say, dish cloth), through increased usage became joined (dish-cloth) and then, eventually, closed (check your dictionary!). You can see this process in action with the compound phrase Web site; although still designated open in the dictionary, the AP Style Guide (used primarily by newspapers and some magazines) recently announced a move to … website. And so it goes; I suspect dictionaries may not be far behind.

When to do what can be tricky; I’m often surprised when I check something I thought I knew. So when writing or self-editing, you should simply question every compound. The Chicago Manual of Style tells us that “the most common spelling questions for writers and editors concern compound terms” and “the first place to look for answers is the dictionary.” (There’s a concept!) Chicago goes on to cite many definitions and rules, ending with a fabulous list that should answer any compound word question not specifically addressed in your dictionary. (I call it fabulous because I am, honestly, a Chicago geek; these particular pages in my CMS are stained and wrinkled, such is my devotion.)

If you don’t know about the CMS, now’s the time: the sixteenth edition just shipped last month. The ultimate reference book for book publishers, it’s been produced since 1903, and is updated on average every six years (I just did the math). You can subscribe to it online if you’re so inclined. And by the way, if you’ve never checked “Chicago Style Q&A”—in which someone at the University of Chicago Press undertakes to answer questions of style and usage from users who can’t seem to find what they’re looking for in the book (it’s over 900 pages, after all)—you simply must stop by the Web site sometime. Questions are answered with a sly wit; it’s often quite hilarious.

Tweet: There are all sorts of compound words: Open, closed, hyphenated!
Tweet: When writing or self-editing, you should question every compound.

Disclosure of Material Connection: I have not received any compensation for writing this post. I have no material connection to the brands, products, or services that I have mentioned. I am disclosing this in accordance with the Federal Trade Commission’s 16 CFR, Part 255: “Guides Concerning the Use of Endorsements and Testimonials in Advertising.”