URLs

Q. I noticed an article about CMOS that referred to this website address without the “www.” See University of Chicago Magazine, August 2003, page 40: “A New Web Site (chicagomanualofstyle.org) . . .” Is this okay?

A. Many URLs that include “www” have been designed to work without it; for example, paste “chicagomanualofstyle.org” into your address bar and you’ll automatically get redirected to “http://www.chicagomanualofstyle.org/” (followed, in this case, by “home.html”—the name of the home page document itself). This is not true for all addresses, however; ours, like many, has been programmed to do that. It is our recommendation, therefore, to include not only the full name of the domain server but also the protocol in any URL: for example, http://www.chicagomanualofstyle.org/ (note the final slash, which indicates a directory-level URL). This recommendation applies to scholarly writing and source citations. In journalism, it can be acceptable to abbreviate, especially in print. For a full discussion of URLs and related matters, see chapter 14 in CMOS.

[This answer relies on the 17th edition of CMOS (2017) unless otherwise noted.]