Copyeditors typically work in a word-processed manuscript, making and suggesting changes directly in the document. Proofreaders come in at a later stage, after the manuscript has been converted and formatted for publication in a program like Adobe InDesign.
In the old days, authors wrote out their source citations from scratch, and editors checked them to make sure they were correctly formatted. Now there are tools that will do this for you, from online “Cite” buttons to full-featured citation management apps.
A defining feature of any style is how it capitalizes words in the titles of books, articles, and other works. Most recommend a variation of title case, or what CMOS has traditionally referred to as headline style.
From the perspective of writers and editors, URLs do their best work behind the scenes or just off the page, in a browser’s address bar. In that role—as an internet address that will take you to a specific page online—it doesn’t matter all that much what a URL looks like so long as it works.
To a copyeditor working on a manuscript, a space is usually just a space, and line breaks are random, fluid occurrences that vary as text is added and deleted and moved around. Designers and typesetters will take the edited text and make it pretty for publication, in part by applying different types of spaces as needed to prevent unwanted breaks.
A prefix is a partial word that joins to the front of another word (and sometimes a phrase) to create a new word with a different meaning. The pre- in prefix is a prefix, for example.
Grammatically speaking, “appositive” is a fancy word for “equivalent.” For example, when we refer to your dog Smurf, “Smurf” and “your dog” are appositives—or the same thing (or animal, in this case) restated in different words.
In editing as in life, things tend to come in pairs. Life has its ups and downs, left and right, sea and land, victory and defeat. In editing you have capitals and lowercase, justified and ragged right, insert and delete.
The seventeenth edition of CMOS was the first edition to rule explicitly on whether “too” in the adverbial sense of “also” should be set off by commas. The rule applies also to “either,” which as an adverb can play a similar role in a sentence or clause.
Chicago’s main system for citing sources—and the subject of chapter 14 of CMOS—consists of numbered notes in the text and a corresponding list of sources in a bibliography.