As a professional typographer and proofreader (I know; rare and disappearing breeds, especially for being both at the same time! And yes, I’m also a graphic designer), I tend to follow what are called “manuals of style.” For English, my reference is the Chicago Manual of Style, now in its 17th edition.

In it, one can read that “extra-,” among many other such particles, is a prefix, i.e. that it should be one word with whatever follows it. A good example is “extraordinary,” as “extra ordinary” would have quite the opposite meaning!

However, I see “extra” written separately from or hyphenated to many words, e.g. “extra virgin olive oil” or sometimes “extra-virgin olive oil.” Both of these, according to the CMS, are considered wrong.

Today I typeset a document that I partly rewrote from an older version, and sent it to a colleague for proofreading (one never proofreads him-/herself!). She pointed out that I had, in her opinion, misspelled “extramild,” and when I told her that “extra-” is a prefix, she objected that she never had any “extramild salsa” but that it was always “extra mild.” When I told her that it’s spelled this way “because people don’t write properly,” she said that languages do evolve and change with time (or we’d still be grunting like cavepeople, I suppose), and that, loving linguistics as I do, I should understand that—which I think is no excuse for not writing properly.

So my question here is: How can I justify “extramild,” “extravirgin,” and other such constructions without being told that “I don’t see it spelled that way”? (This also applies to many other prefixes, such as “anti-” and “mid-,” for example.)


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    I don't have a CMS-17 ready to hand, but I think you are overgeneralizing from something within it. There is a process by which many compounds start out spelled open (with a space), then become hyphenated, and finally get spelled closed. (Have you never seen "today" hyphenated "to-day" in older texts?) In any present historical moment, different compounds are in different stages of that process. And “In words, as fashions, the same rule will hold; / Alike fantastic, if too new, or old: / Be not the first by whom the new are tried, / Nor yet the last to lay the old aside.” Commented Apr 14, 2021 at 11:29

1 Answer 1


How can I justify “extramild,” “extravirgin,” and other such constructions without being told that “I don’t see it spelled that way”?

You can justify it by saying that the house style guide is the Chicago Manual of Style, and that it requires those constructions.

But you shouldn't do that, because you're wrong. Extra is not always a prefix. Sometimes it's an adverb. As a prefix, it means "outside," as in extrajudicial, extramarital, or extrasensory. When it means "more" (of some adjective), it's an adverb, and it's generally written, like most adverbs, as a separate word, or sometimes with a hyphen.

It may help to note that these words have different etymology. The prefix meaning "outside" comes from Latin exter, meaning "outside," while the adverb meaning "more" originates as a truncation of extraordinary.

  • You’re absolutely right, and I’m cursing myself right now for not thinking of that before. Thank you! :) Commented Apr 14, 2021 at 22:20

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