Larry, I know you disapprove of US without the periods, but I think it should be written without the periods anyway -- today all newly coined abbreviations have no full stops -- only ones which go back decades or centuries do. We don't write U.N., we don't write E.U., so why write U.S.? Periods in abbreviations are going out of fashion; and I wouldn't use them at all except for e.g., i.e., viz., ibid., op. cit., etc. -- Simon J Kissane


Is it true that abbreviations are used with a period mark but acronym do not?


See The Chicago Manuare used, at least in American English, in abbreviations of country names, persons, eras (e.g., "B.C."), and in other cases, but not in acronyms like NATO. It is just not as simple as you want it to be. I don't know what British style guides would say. --Larry Sanger


There is no argument on using period in abbreviations such as in abbr. lb. oz. Mass. etc. etc. The real question is whether US is classified as an acronym or an abbreviation. The use of US falls into the acronym catagory because it fits in the definition of acronym. The American Heritage Dictionary of the English Language lists US, U.S., USA and U.S.A. as entries. Perhaps, U.S. and U.S.A. are abbreviations and US and USA are acronyms.


Unless you are an expert on usage, I don't see what the point of debating this is: if you're unsure on the question, and you're not an expert, then you look it up in an appropriate reference. The appropriate reference in this case is not a dictionary but a copyeditor's guide, of which CMS is just one. --LMS


Regarding "Mass.", above, which is an abbreviation of "Massachusetts": a permissible abbreviation is "MA", which is the state's postal code. States in the U.S. all have two-letter postal codes, and those are increasingly used (in business correspondence, anyway) in place of the old-style abbreviations: "PA" instead of "Penn.", "DC" instead of "D.C.", etc. -- RjLesch


Recall that many years ago the Post Office released statements listing the new abbreviations they had come up with and requesting that people use the new abbreviations rather than the old ones. I recall getting several notices about it in my box, as if it were some earth-shattering development. ;-) I'd be hard pressed to say when this occurred exactly; certainly it was more than 10 years ago. --KQ


The problem with style manuals is that they tend to be elitist and traditionalistic -- they don't reflect English as its actually used, but rather as some group of "experts" believe it should be used. Dictionaries or observing actual usage are much better sources -- Merriam-Webster for one lists US without any periods. As to British English, the BBC writes US on its website, and as to Australian English so does the Sydney Morning Herald. But I don't think this is an American vs. British English thing because plenty of Americans write it without the periods as well. -- Simon J Kissane


I don't know why you say style manuals tend to be "elitist and traditionalistic." You probably have seen some lately? The correct American English usage is "U.S." I will continue to change these personally.  :-) Nuff said. --LMS


style manuals are the only thing standing between me and chaos. I read approximately 150 student papers per term - thankfully not ALL of them are research papers with bibliographies. Without a style manual to hurl at them I could not sort out whether they were referring to factoids discovered (a) on the web, (b) in a newspaper (c) in a journal (d) in a book. I can tell the difference without my glasses if they have followed an acceptable citation method. Call it elitist. Call me a fascist. I'll still demand a style manual. Now on wikipedia, it should be endless fun changing each others U.S.s back to USs. Me, I'll write content (if I'm being good). --MichaelTinkler


I might just write it U.S. or US for no reason whatsoever. Phase of the moon maybe. Life is very short, too short to worry about debates of interest only to the grammarati. What you say!


Well, don't let me stop you from writing whatever you like. I simply reserve the right to change it to what I think it should be.  :-) Michael does have the better attitude, though, I fully admit.  :-) We need all kinds here. --LMS


The ISO international country code for the United States of America is "US". That is also the code used on the net for its TLA, i.e. xxxx.state.us <-- note no periods. Likewise Britain is UK, Europe is EU when referred as an entity, United Nations is UN, Canada is CA, and these country codes are used all over the world. Unless you insist on proliferating the conventions of each nation, which will surely happen if US standards are imposed here, it makes sense to use w:International English, which includes by the way many British spellings: honour, flavour, neighbour. These too must eventually be standard if we want to be understood all over the world, as that's what people learn in the former British Empire, i.e. most of the planet, and from British journals, e.g. w:The Economist. Likewise we should stick to metric where we can.


The majority of non newspaper style guides (Scientific, British, Chicago) say to go with US rather then U.S.. (note the problem the period in U.S. causes in that sentence; that is why.) "Use no periods with abbreviations that appear in full capitals, whether two letters or more and even if lowercase letters appear within the abbreviation: VP, CEO, MA, MD, PhD, UK, US, NY, IL" "The Chicago Manual of Style" (2017)

The main exception is when using quotes from sources using traditional state abbreviations and legal-context citations.


See also : Wikipedia Commentary