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I am writing an essay where I need to make a reference to the United States of America. Often I hear this shortened to the US, but sometimes people also say the USA. Are there any difference between the use of the two? Is one more formal or correct than the other?

As a random example of what I want to write is Is the US the most beautiful country in the world?

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I think if you are writing an essay you should rather use "United States" or "United States of America" rather than abbreviating. – major-mann Mar 21 '14 at 20:40
see this Ngram Clicking on "case sensitive" for when the article is capitalized, the results remain pretty much the same. – Mari-Lou A Oct 21 '14 at 17:33
I suspect that if you scanned this board you would find that "US" (without periods) is by far the most common representation. But, of course, most writing here is somewhat informal. – Hot Licks Jan 20 at 22:51
up vote 15 down vote accepted

Here is an interesting discussion of US versus U.S. versus USA versus U.S.A. from Wikipedia: Manual of Style:

In American and Canadian English, U.S. (with periods) is the dominant abbreviation for United States. US (without periods) is more common in most other national forms of English. Some major American guides to style, such as The Chicago Manual of Style (16th ed.), now deprecate U.S. and prefer US. Use of periods for abbreviations and acronyms should be consistent within any given article, and congruent with the variety of English used by that article. In longer abbreviations (three letters or more) incorporating the country's initials (USN, USAF), do not use periods. When the United States is mentioned with one or more other countries in the same sentence, U.S. or US may be too informal, especially at the first mention or as a noun instead of an adjective (France and the United States, not France and the U.S.). Do not use the spaced U. S., nor the archaic U.S. of A., except when quoting. Do not use U.S.A. or USA, except in a quotation or as part of a proper name (Team USA), as these abbreviations are also used for United States Army and other names.

The Chicago Manual of Style, 15th Edition (2003) comes out strongly in favor of spelling out United States (rather than abbreviating it) when the term is used as a noun and not an adjective:

15.34 "U.S." or "US." Except in scientific style, U.S. traditionally appears with periods. Periods may nonetheless be omitted in most contexts, Writers and editors need to weight tradition against consistency. In running text, the abbreviation (in either form) is permissible when used as an adjective, but United States as a noun should be spelled out.

Words Into Type, Third Edition (1974) takes an even stronger anti-abbreviation position:

In the most formal writing, United States should always be spelled out; in other works U.S. is gaining currency as an adjective when preceding a government agency, department or organization or the name of a government vessel. [Examples omitted.] When used as an adjective with general terms, United States should be spelled out. [Examples omitted.]

Both Chicago and Words Into Type have so little regard for USA that they don't even mention it as an option in their discussions of abbreviations for countries.

The Associated Press Stylebook (2006), however, accepts both U.S. and USA as nouns, and seemingly views them as equally valid designations:

U.S. The abbreviation is acceptable as a noun or adjective for Unites States.

USA No periods in the abbreviated form for United States of America.

Nevertheless, I have never seen a style guide that approved of using USA as an adjective.

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Good answer. But I hate it. It speaks a very sad truth that I don't want to deal with. – uSeRnAmEhAhAhAhAhA Mar 22 '14 at 2:52
@Spike: What sad truth? – 3Doubloons Mar 22 '14 at 4:02
We like to think that we're smart, but we can't really decide on whether or not to use a period or two. Throughout School they teach us to use periods in between U.S, for example, and give us low marks if we forget. But in recent years I've noticed more and more people not using periods at all, and not even bothering to capitalize abbreviations, and even failing to use punctuation. There's a reason they were used in the first place, why can't we just stick to it? It made sense then, and nothing has really changed, so why doesn't it still make sense? – uSeRnAmEhAhAhAhAhA Mar 22 '14 at 4:57
@deletethisaccount Well, the reality is that language has fashion just as clothes do - how one writes, how dots and slashes are used, is inextricably tied to our life experience and the time in which we live and were raised. Your preference to do as you were taught in school, for instance, is a good example of this. Fashion is not set in time, and what was judged as refined in clothing might now be seen as worn, tired, or unnecessarily formal and thus out of place. Sadness is the result when we try to treat something impermanent as though it were eternal. It helps to think: it's just a dot... – BrianDHall Oct 21 '14 at 14:42
Indeed, @BrianDHall. Most punctuation, a great deal of spelling, and most of what was traditionally taught in schools as grammar, are all fashion. – Colin Fine May 12 at 22:53

I would claim that the term "U.S." is far more common than "U.S.A.", and is in fact how the U.S. Government refers to itself.


  • The U.S. Department of State (http://www.state.gov/)

  • The U.S. Department of the Treasury (http://www.treasury.gov/Pages/default.aspx)

  • The U.S. Department of Commerce (http://www.commerce.gov/)

  • The U.S. Department of Defense (http://www.defense.gov/)

  • That the President is referred to as the President of the United States (POTUS) not "POTUSA" (which is apparently the name of a band). For an Atlantic article about the ascention of this anacronym to the everyday vocabulary of Washington and White House government workers and staff, see here: http://www.theatlantic.com/past/docs/issues/97oct/wordimp.htm

  • The phrase "U.S." / "US" (in quotes) has 4,390,000,000 results on Google [21-3-2014], whereas "U.S.A." / "USA" has only 792,000,000 results [21-3-2014].

  • David M's commented that Mexico is also a "United States", but consider that Mexico is also a "United States in America".

All of this being the case, your audience matters. For example, if you're giving a talk in Venezuela or Cuba, you might err on the side of directly saying "United States of America" to avoid the implication that "the U.S. is important enough that just writing U.S. is a sufficient descriptor" (regardless of whether or not this is the case).

Finally, consider how it would sound to refer to "Russia" as the "Russian Federation" (+ Crimea?). If not technically correct, "Russia" is by far more common and well-understood term. That said, the U.S. does not have anything akin to Russia's history, and there are certain ethnic implications if someone is "Russian" though this is not necessarily so if someone is "American" or "from the U.S.".

Let me add one more thing: the term "USA" seems, at least to me, to have patriotic overtones. Consider the phrase "Made in the USA" (16 million hits on Google [21-3-2014]) or the U.S.A.! chant (http://en.wikipedia.org/wiki/U-S-A!_(chant)). So this may be worth keeping in mind depending on your audience (I'd invite others to criticize this comment).

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It may be worth distinguishing between U.S./U.S.A. as a noun and as an adjective. According to Garner's Modern American Usage: "'U.S' is best reserved for use as an adjective {U.S. foreign policy}, although its use as a noun in headlines is common." I don't know if I agree with his advice (U.S. as a noun seems fairly natural to me) but the distinction is something that your relative frequencies wouldn't necessarily reveal, and POTUS is the only one of your examples where it's used as a noun. – Curtis H. Mar 21 '14 at 17:10
@CurtisH. That's a good point. However, as you say, I think it's fairly natural to use the term "U.S." as a noun. There are a number of examples e.g. in today's Wall Street Journal. – AM55 Mar 21 '14 at 17:13
Regarding talking to people in Venezuela, Cuba, or elsewhere in South/Latin America, I would actually say it's better to use "US". In most Spanish dialects it's called "los Estados Unidos" (the United States) and citizens of the US are called "estadounidense" (literally, United-Statesian). The use of "America" or "americano" are often offensive because it implies the US is the only part of the two American continents that matters. – Oblivious Sage Mar 21 '14 at 21:14

I work as an editor on international journals, so am quite interested in this topic. I read that the full name of the country is "The United States of America" and that in 1777 the Articles of Confederation announced, "The Stile of this Confederacy shall be 'The United States of America'". In Europe, we therefore usually employ the abbreviation USA, limiting US (which we understand to be an informal styling) to adjectives, e.g. US Fish and Wildlife Service, US Army, US dollar. The term US will always logically have more Google hits than USA simply because of this adjectival use, but those outside of the USA tend to use USA rather than just US when referring to the country. The journals I work for avoid using periods or stops between letters of abbreviations - deemed unnecessary.

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For most usage in English, the abbreviations are identical. The United States of America is the only country on either continent with "America" as the only distinctive proper part of its name, and certainly the only English-speaking country commonly called that.

Within a given work, however, it's far more important to be consistent than to be correct. The practice for legal documents is to parenthetically note the abbreviation or pronoun you use after its first instance, and then use such throughout. For a simple essay you can skip the notation of a common abbreviation, so long as it's not confusing.


The United States of America is made up of several states. Some of these, like Michigan (MI) and Mississippi (MS) have very similar abbreviations. It's not uncommon even for those familiar with the USA to be unsure if MI or MS is the one with Detroit or the one with Mardi Gras.

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First of. And I can't help it. The US of A is a federation of states.

Is the US the most beautiful country in the world?

I'm not an english native but I'd guess that country comes from county which is / was a local administrative region.

Since the US of A consists of a lot of counties / countries (states) you probably are better of in talking about the individual examples vs saying the whole big landmass covered by US of A is the prettiest landmass on the planet. How do you want to quantify that?

US of A is a political, economical and societal construct. If you want to talk about numbers of citizens, politicians or height of state debt then you can use the US of A because these numbers directly apply to this construct. Otherwise just talk about specifics like the central park is the biggest park in New York City which is located in,…, in the North West of the US of A.

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Country and county are not interchangeable in US English. A county is a local administrative region of a (U.S.) state, whereas country can be used synonymously with 'nation'. Referring to the U.S.A. as a single country is both natural and common. – Curtis H. Mar 21 '14 at 17:14
County comes from medieval Latin comitatus which meant a territory ruled by a count. Country comes vulgar Latin contrata- "the land opposite". – Laure Mar 21 '14 at 19:23
@CurtisH Though Country, Nation and State can be (and frequently are) used interchangeably they can also be distinguished technically as "Country" to denote the land or the physical area, "State" to refers to its government, and "Nation" to it's people and their common identity. At least that's what they taught me in college when I was taking courses on the rise of the modern nation-state. – RBarryYoung Mar 22 '14 at 0:53

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