Correct capitalization for "of" in an acronym definition
First, some definitions from the Chicago Manual of Style:
- acronym refers to terms based on the initial letters of their various elements and read as single words (AIDS, laser, NASA, scuba);
- initialism refers to terms read as a series of letters (AOL, NBA, XML);
- contraction refers to abbreviations that include the first and last letters of the full word (Mr., amt.).
As for the capitalization of these constructs, CMS has these recommendations:
Initialisms tend to appear in all capital letters, even when they are not derived from proper nouns (HIV, VP, LCD). With frequent use, however, acronyms—especially those of five or more letters—will sometimes become lowercase (scuba); those that are derived from proper nouns retain an initial capital. Chicago generally prefers the all-capital form, unless the term is listed otherwise in Webster’s. [NAFTA (not Nafta)]
On the other hand, if the words in a spelled-out version of an acronym or initialism are not derived from proper nouns or do not themselves constitute a proper noun (as in the official name of an organization), they should generally be lowercased, even when they appear alongside the abbreviated form. [transmission-control protocol/Internet protocol (TCP/IP)]
So, whether CAOWS is:
- an acronym, pronounced cows
- an initialism, pronounced "SEE-AY-OH-DUBYA-ESS"
the Chicago Manual, at least, would recommend you write:
My coworker Steve suffers from Complete Avoidance of Work Syndrome (CAOWS).
Note that in Nathan's comment, it's necessary to lowercase DoS (an acronym for denial-of-service) to disambiguate it from DOS (an acronym for disk operating system). I don't think CAOWS has any such problem.
I wouldn't capitalize the o in "of".
Here's a well known example.
TOEFL:
Test of English as a Foreign Language.
Typically, prepositions and articles should not be capitalized.
For a comprehensive capitalization rule list, see here.
If CAOWS were your acronym, then you would capitalize the O in "Of". If we use WINE as an example (Wine Is Not an Emulator), the "I" in "Is" is capitalized, but not the "a" in "an".
When writing out an acronym or initialism you do not capitalize the letter "o". As mentioned already, TOEFL is a good example of this as it is written out as Test of English as a Foreign Language (Cambridge University Press, About.com).
Note that the use of the letter "o" in the actual acronym or initialism is far more flexible and can be divided into three categories:
- The "o" is consistently capitalized, as is done in TOEFL.
- The "o" is omitted, as in ASEAN (The Association of Southeast Asian Nations).
- The "o" is printed in upper or lower case. For example, both LoA and LOA are common initialisms for Letter of Approval.