An acronym is a word made up of fragments of other words and can be read as a word (that is, without spelling). Acronym is a procedure of word formation by abbreviation of other words. It has a great vitality in our days and, therefore, is giving rise to a huge number of neologisms.
They are acronyms, for example:
The examples above will help us to introduce the characteristics and types of acronyms.
The most typical thing is that the acronyms are formed by taking the initial of each of the words that we are integrating in the new unit. Thus, FIFA is constituted from the first letter of the International F ederation of Football Association . FIFA is an acronym because we pronounce [fífa] and not [éfe-í-éfe-á]. We can conceive of this type of acronym as a special case within the more general category of acronyms.
Actually, what has been selected in FIFA are the initials of the significant words that constitute the underlying expression. Instead, we have discarded the preposition of. This is the usual behavior, but we can also find cases in which prepositions and other grammatical words are used. In Spain there is in 2019 an organization called FECYT (Spanish Foundation for Science and Technology). We see that here the conjunction and has been included in the acronym , while the article la and the preposition para have been discarded.Why? This is simply the result of arbitrary decisions. What is sought is to facilitate reading and, above all, pronunciation. Those who favored FECYT over FECT wanted an acronym [fezít] and not a vulgar acronym: [éfe-é-zé-té].
Returning to FIFA, we will notice that it is written in capital letters. In this, too, it behaves like a typical, central example. When we think of abbreviations and acronyms, the first thing that comes to mind are sequences of capital letters. In the current spelling, we don't separate those caps with periods.
The distinguishing feature of acronyms is that we can read them like ordinary words. This favors that they end up converted into that: normal and current words that are integrated into the vocabulary of a language. We have an example of this in UFO. This word began its journey in our language with the spelling OVNI, entirely in capital letters. In this way, it was intended to make it clear that what was behind it was the expression unidentified flying object . With the passage of time, the awareness that UFOsit was there to represent a complete expression. We have already gotten used to treating this unit as just another word and only recover the underlying expression when we stop to think about it. That is why today we write UFO in lower case: the spelling reflects that there has been a change in the status of this unit within the lexicon of our language. Other similar examples are AIDS (< acquired immunodeficiency syndrome), takeover bid (< takeover bid), ICU (< intensive care unit), etc.
But we are not done with UFO. It is also noted that this word is perfectly integrated among the nouns of our language because it forms a plural that, in addition, is subject to the general rules. Who sees a UFO can also see several UFOs (they say that the most difficult thing is to spot the first one, from there everything goes smoothly).
The fact that acronyms are treated like any other word also has consequences for graphic accentuation: they will be subject to accentuation rules. For example, laser has an accent because it is a serious word ending in erre. And if it is necessary to divide into syllables, it is divided; without going any further, when one of these words does not fit on a line (lá- / ser). Attention: let us not forget that all these orthographic indications refer to the acronyms that are integrated into the lexicon, not to those that are written entirely in capital letters.
Mercosur is similar to UFO in that its spelling is adapted: it has lost all capital letters, except for its initial. This one does keep it because it is a proper name that refers us to the expression Common Market of the South. But Mercosur differs from our previous examples in that it is formed by taking more than one letter from each of the underlying words. This is what allows, precisely, to create the acronym, because otherwise we would have to deal with the acronym MCS.
Mercosur takes more than one letter, it is true, but they are initial letters. Instead, portuñol is representative of our last type of acronyms. Here what is being integrated is the beginning of a word (Portuguese) and the end of another (Spanish). The same happens with muppet (< television + doll) and office automation (< office + computing).
In addition to the types mentioned, there are other mixed ones. For example, Fundéu is formed with several letters of a word and the initial letter of the rest: Fundación del E spañol U rgente . Reviewing all the casuistry would now take us too far.
Many of the acronyms that we find today in our language are, in fact, loans from English. Earlier we used laser as an example, which comes from the English expression light amplification by stimulated emission of radiation or, what is the same, 'amplification of light by induced emission of radiation'. Other examples are radar (< radio detecting and ranging, that is, 'detection and location by radio') or emoticon (< emotion + icon).
And I could go deeper because the subject is complex. But I think that with this we already have a fairly complete idea of what acronyms are.