Given the location and the period, I think it's likely to be a commonly-used variant of "£sd" for "pounds, shillings, and pence" - that is, money. The abbreviation comes from the Latin librae, solidi, denarii.
The important point to remember is the following:
Written language is a representation of the spoken word.
Thus, the answer is "If the word following the indefinite article begins with a vowel sound, use an; if it begins with a consonant sound, use a."
In the case of initialisms and acronymns, use the exact rule above. For initialisms (e.g. "US"), the ...
I seem to remember the old askoxford.com site said either was acceptable: CDs and CD's.
But now the replacement Oxford Dictionaries Online firmly suggests to avoid the apostrophe except in a few special cases:
Apostrophes and plural forms
The general rule is that you should not use an apostrophe to form the plurals
of nouns, abbreviations, or ...
It's slang for (and an abbreviation of) Original Gangster.
someone who has been around, old school gangster
Commonly used to refer to someone who is not a gangster, but is considered highly skilled in a particular area.
BCE/CE usually refers to the Common Era (the years are the same as AD/BC). That is, BC is usually understood to mean "Before the Common Era" and CE to mean "Common Era," though it is possible to reinterpret the abbreviations as "Christian Era."
The simplest reason for using BCE/CE as opposed to AD/BC is to avoid reference to Christianity and, in particular, ...
Though the word personal is repeated in the expansion "personal personal computer", the two repetitions use different meanings of the same word. The first personal means "owned or used by a specific single person" (definition 1 here), while the second indicates "designed to be used by a single person" (definition 2 here, again). Both instances are required ...
The answer lies in the history of how apostrophes have been used, and how this has then changed:
A Brief, but not that Brief, History of the Apostrophe in English
There’s a myth that the apostrophe is only used for elision. It’s a pretty useful myth, because believing it is unlikely to lead you into mistakes if you are using the most popular styles today, ...
It all starts with a little slang hep:
"aware, up-to-date," first recorded 1908 in "Saturday Evening Post,"
but said to be underworld slang, of unknown origin.
Variously said to have been the name of "a fabulous detective who
operated in Cincinnati" [Louis E. Jackson and C.R. Hellyer, "A
Vocabulary of Criminal Slang," 1914] or a saloonkeeper ...
United Nations is an expansion of U.N.
United Nations is an expanded form or full form of U.N.
I say "an" because U.N. can represent things other than "United Nations."
I think more commonly we would say
United Nations is U.N. spelled out.
United Nations is what U.N. stands for.
The Chicago Manual of Style says:
Capital letters used as words, numerals used as nouns, and abbreviations usually form the plural by adding s. To aid comprehension, lowercase letters form the plural with an apostrophe and an s.
The lowercase letter exception presumably exists because omitting the apostrophe can make the sentence much harder to understand (...
I agree with Wikipedia, wordreference and CMOS - acronyms and initialisms are "regular" nouns; plurals are formed by adding "s".
Checking Google Books for actual usage in a relatively "contentious" case, I searched for:
"OSs" unix windows linux 3120 written instances
"OSes" unix windows linux 1060 instances
"OS's" unix windows linux 520 ...
Generally the article is not used with acronyms (initials that can be pronounced as a word), whereas it is with initialisms (initials where the letters themselves are pronounced). I would actually use the article with 'ESA' in the examples you gave, and so 'NASA' (acronym) doesn't get an article, but 'FBI', 'ESA', and 'DDR' (initialisms) do.
That said, ...
My understanding, and the way things are typically named at least in the context of computing (I'm a programmer by trade), has always been the following:
PDT = Pacific Daylight Time = fixed to UTC-7
PST = Pacific Standard Time = fixed to UTC-8
PT = Pacific Time = a general reference to the time zone, which alternates between PDT and PST depending on the ...
CSS here has evolved as a noun independent as to what it means as an acronym. It refers not just to "cascading style sheets" themselves, but to the entire system and infrastructure for styling web pages.
In short, it is a singular noun that has come into existence due to common use.
Here is a similar example: Imagine a company called "Unlimited Designs." ...
It doesn't matter how many different authorities/style guides are cited - usage in this area has never been fixed, so it doesn't mean much to suggest the "rule has changed over time".
The use of apostrophes has always been less common, but it's been around at least a century (there, for example, the 1700's). It's also worth noting that (particularly in ...
L.S.D. was the standard abbreviation for "Pounds, shillings, and pence".
Note that wikipedia claims it was usually written £sd and "sometimes" as Lsd. That was not my experience - I would have said "l. s. d." was at least as common. (Source: I was 13 when the UK decimalized).
Setting aside the question of "correct" pronunciation, we can look at actual usage and draw some conclusions. Although this is a question about pronunciation, we are lucky in that we can look at written usage to get clues about pronunciation: if someone writes "an LED" we can assume they would have used the spelling pronunciation, and if they write "a LED" ...
Q.E.D - Quod erat demonstrandum - is put at the end of of a proof to signify that what we attempted to prove has been proven.
Q.E.F. - Quod erat faciendum - is a term that is used in geometric proof to signify that the geometric construction has been completed. It is a rarely used English abbreviation.
From the article the correct translation is Q.E.F. but ...
Vincent McNabb is correct. If you want evidence based on "credible and/or official sources" that this is the rule followed in formal English writing, here is my suggestion.
I ran Google searches on Google Books only, meaning the bulk of the search will be against professionally edited and published works, not random web sites. I searched only for phrases ...
My answer focuses on the header question about decades—which is the question that most readers will probably expect to find answers to here. With regard to decades expressed in numerals rather than spelled out in letters, some style guides recommend omitting an apostrophe, while others recommend including it. For example, from The Chicago Manual of Style, ...
It could be characterized as a rebus
a riddle or puzzle made up of letters, pictures, or symbols whose names sound like the parts or syllables of a word or phrase [Merriam-Webster]
While a rebus often contains images, letters being used to represent syllables is common.
In particular, the Encyclopaedia Britannica states
Literary rebuses ...
It doesn't make any difference at all whether the article is modifying an acronym, an initialism, a proper noun, a French borrowing, or anything else. English article form is determined solely and entirely by pronunciation. And not at all by spelling.
The rule for the pronunciation of articles in English -- definite and indefinite -- is that they have one ...
The OED has hooray as a variant of hurrah meaning goodbye, from 1898. Hurrah and hurray are a shout or cheers of encouragement, from huzza of 1573.
Hip, also hep, is an exclamation or a call to another and the same as the Latin eho, heus!, according to Johnson. From 1752. It's also an exclamation, usually repeated three times to introduce a cheer, from The ...
An acronym is a word formed by the initial letters of other words, such as Nato (North Atlantic Treaty Organisation). Note that this is different to an initialism where the initial letters are spelled out, as in BBC for example.
A backronym is where the word comes first, and the initial letters are made to fit the word. An example is Alex the parrot (...
Since this is a question about acronyms, and the Federal Government's bureaucracy is notorious for using acronyms, I decided to look up the answer in the United States Government Printing Office (GPO) Style Manual (2000).
Rule 8.11 of the GPO Style Manual states: "While an apostrophe is used to indicate possession and contractions, it is not generally ...
A backronym (Backward acronym or blend of back and acronym) is a term for a word which has been turned into an acronym by inventing an expansion, rather than the other way around. An example given by Wikipedia involves a backronym invented by NASA (itself an acronym - a word formed from initial letters of words and pronounced as a word - for the National ...
My copy of Practical English Usage, 2nd Edition (Michael Swan, 1995) says this:
Apostrophes are used in the plurals of letters, and often of numbers and abbreviations.
He writes b's instead of d's.
It was in the early 1960's. (OR ... 1960s.)
I know two MP's personally. (OR ... MPs.)
Using Amazon's Search Inside The Book I can see that ...