Should “Light Bulb” Be One Word, or Two?
Why do most people spell “light bulb” like that, as an open compound? Because most dictionaries treat it that way. But the dictionary used by most American publishing companies and periodicals as the resource of record, Merriam-Webster’s Collegiate Dictionary, and its online equivalent, spell it as a closed compound. Despite that fact, even in books, magazines, and newspapers, and on professional websites, many of which presumably adhere to Merriam-Webster, I often see it styled “light bulb.”
If it’s usually spelled that way, even in well-edited publications, why doesn’t Merriam-Webster cave in? Decisions by descriptivist dictionaries about how to render words are based on popular usage, but because dictionary staff have tens of thousands of words to monitor, there’s often a lag of years before these references update a word’s spelling or definition according to a shift in usage.
Eventually, therefore, Merriam-Webster will likely treat lightbulb as two words. Is that a problem? Well, words frequently undergo alterations, but this one is anomalous, because the trend in word compounds is that they normally begin in open form. Then, they may or may not have a transitional hyphenated form before (usually but not always) becoming closed compounds. Here, the process has reversed itself.
I can’t hold back the tide, but I can do what any conscientious (and sensible) editor does: I minimize exceptions — unless a writer or a project editor strongly prefers the variant. Otherwise, how do I form the term? Lightbulb, because I consult Merriam-Webster’s, and that’s how it’s treated in that resource. What do I do if I see it spelled “light bulb” in a manuscript I’m editing? I correct it. Consistency is a hallmark of high-quality writing, and contributing to high-quality writing is my responsibility as an editor (and yours as a writer).
Is this a lot of trouble over one word (or is it two words)? I don’t dwell on it; this discussion is merely intended to provide an example for a lesson for writers: Today, do things the way you did them yesterday, and tomorrow, do the same. Break rules as necessary, of course, but you should know them before you break them, and if you do break them, have a good reason to do so.
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