It is neither the case that the word "acronym" is ambiguous, nor that
FORTRAN et al are not acronyms.  Please see:

http://www.dictionary.com/cgi-bin/dict.pl?term=acronym
http://www.dictionary.com/cgi-bin/dict.pl?term=initialism
http://www.dictionary.com/cgi-bin/dict.pl?term=solecism

Alternatively, see http://www.m-w.com, http://www.oed.com (if you feel like
paying), or a printed dictionary.

Acronyms may be made from the leading character(s), not leading character of
words.  As for "Nato", I believe that to be entirely erroneous.  According
to both rules and usage, the correct capitalization is NATO (see
www.nato.int).  With respect to PL/I, if one wishes to say that the use of
an arabic instead of roman numeral is a solecism, I might concede the point.

Language is about communication.  In order to communicate, we must have
common definitions.  We call this concept volcabulary, and we write down the
agreements in things called dictionaries.  An acronym is a defined concept,
whose agreed upon definition can be found.

English is not a simple language.  Misuse of the language happens all the
time; probably in this message.  The chronic misuse of the language is not a
self-justification for the continued violation of its rules.

In any event, this discussion is off-topic.  And since there are actually
Squeak-related threads starting up, we might was well let this one die off
before it gets really trite.  After all, capitalization is about style.  As
Warriner's observes: "[Many] uses of capitalization are merely conventions;
i.e., they are usages customarily observed by educated people for no other
reason than that they are customary."  Given the state of education in the
USA, I'm happy enough that we all use a semblance of English.  Some people
believe that schools should concede to local custom, and teach ebonics
instead of proper English.  In comparison to that egregious abandonment of
educational principles, this discussion of capitalization is frivolous.

	--- Noel