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The Chicago Manual of Style: Essential Changes in the 16th Edition

By September 26, 2013 No Comments

Last updated on March 25th, 2019

Chicago Manual of Style Editing Services

These are only some of the more important changes in style contained in the 16th edition of The Chicago Manual of Style. To ensure that your publication is in accurate “Chicago style,” be sure to purchase your own copy of the manual and hire an editor who is an expert in the 16th edition of The Chicago Manual of Style.

The grammar gurus at the University of Chicago Press have recently updated The Chicago Manual of Style to the 16th edition. Many students, authors, and publishers rely on the manual for guidance in writing, editing, and formatting their publications, particularly within the humanities. This short article offers a discussion of some of the more essential changes between the 15th and 16th editions.



  • In the past, there has been some wavering between using one space or two after ending punctuation (i.e., the period, exclamation point, or quotation mark ending a sentence). Although you may have recently learned that the newest edition of the Publication Manual of the American Psychological Association (the APA manual) requires two spaces, the 16th edition of The Chicago Manual of Style has taken a firm stance on using only one space.
  • It has been fairly standard fare to use U.S. as the adjectival form of United States. In this latest edition, the 16th edition The Chicago Manual of Style now recommends that the periods be removed from all abbreviations that once used them.
  • It is now acceptable to use a comma after a question mark or exclamation point that is part of a title, for example, “I really enjoyed reading Who?,” she said.


  • We were told in the 15th edition of The Chicago Manual of Style to use Southern California (with capitalization) when referring to the cultural entity but southern California when referring only to the geographical area. This rule still stands, but now we are also to apply this rule to Northern California/northern California.
  • What was once the cold war is now the Cold War when referring specifically to the Cold War between the United States and the Communist powers.

Check the 16th edition of The Chicago Manual of Style, chapters 7 and 8, for similar changes to individual terms and names.

  • Contrary to what you may find in the dictionary-at least for now-the 16th edition of The Chicago Manual of Style now prefers website, the web, web page, and the net; however, capitalization still stands for the World Wide Web and the Internet.
  • In the 15th edition, geographical bodies were capitalized in isolation (the Colorado River) but lowercased when used with another like kind (the Colorado and Mississippi rivers). The 16th edition of The Chicago Manual of Style now recommends capitalizing in both cases (the Colorado and Mississippi Rivers). This also applies to mountains, fault lines, and so on.
  • Previously, we were admonished never to use a lowercase letter at the beginning of a sentence, but now we have an exception: it is permissible to use trade names that begin with a lowercase letter at the beginning of a sentence and still retain the lowercase; examples include iPod, eBay, and the like.

Plurals and Possessives

  • When you are writing about a word in quotation marks as the word itself, the 16th edition of The Chicago Manual of Style asks that you place the pluralizing –s also within the quotes: “quotidians,” not “quotidian”s
  • The 16th edition of The Chicago Manual of Style has also eliminated its exceptions to using the standard apostrophe s to form a possessive: we are now to use the apostrophe s in all cases marking a singular possessive, even after words ending in an –eez sound: Brian’s, Jesus’s, Socrates’s.
  • The ruling is in! Although using they as a singular neuter pronoun has been encroaching into our spoken and informal written language, the 16th edition of The Chicago Manual of Style is remaining firm that such usage is to be discouraged:

incorrect: When you talk to a customer, remember that they are always right.

correct: When you talk to a customer, remember that he or she is always right.


  • The 16th edition of The Chicago Manual of Style now clearly prefers reverse italics. In other words, if a book title, which is given in italics, contains within itself another book title, that book title is in roman (or nonitalic) type. The same is true, for example, for abstracts set in italics, headings set in italics, and so on.
  • The 16th edition of The Chicago Manual of Style has given us clear guidance on formatting the titles of electronic entities-names of blogs are in italics, whereas names of websites are roman (or nonitalic): Mashable, but Amazon.com.

Notes and References

  • Whereas formerly, the 16th edition of The Chicago Manual of Style used rather different formats for author-date references and numbered notes and bibliographies, the reference and bibliography entries are now identical, with the exception of the placement of the year. In other words, differences in capitalization and use of quotation marks have been eliminated.
  • It is now acceptable to place a note number after an article title, chapter title, or section heading.


By Holly Monty, MA, MAC, ELS

Holly Monty

Author Holly Monty

APA Format, Chicago Manual of Style, Certified Editor in the Life Sciences (ELS), Board of Editors in the Life Sciences. Thesis and Dissertation Editing Services (APA) for Graduate Students. Holly Monty--a Microsoft Word, LaTeX, and APA expert--has worked on books and articles published by many of the world’s leading publishers, including Cambridge University Press, Oxford University Press, MIT Press, W. W. Norton, Sage, John Wiley, Springer, Lawrence Erlbaum, Pearson-Prentice Hall, Praeger, Greenwood, Blackwell, and other top names in academic and nonfiction publishing. To date, she has edited more than 2,000 published journal articles, more than 150 nonfiction books, and a wealth of dissertations and theses. Ms. Monty is proud to have worked with a diversity of students and academics from a broad range of our nation's universities. Given her wealth of experience, she is adept at working within the precise terms of your university's thesis/dissertation guidelines or with the publication guidelines of any peer-reviewed journal. More about Holly Monty

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