Do foreign acronyms take a definite article, and of which gender?

Question

For example is NASA simply "NASA" or "a NASA" or "o NASA"?

What rule(s) determine the answer? The gender of the principal word in the acronym ("agency"/"agência" in this example)? The natural gender of the "word" (e.g. "nasa" would appear feminine), or something else?

Answer 1

Yes, they do. Its gender is determined by the main noun.

Examples

• NASA is an agency (agência, f.) → a NASA
• RAM is a memory (memória, f.) → a RAM
• NATO is an organization (organização, f.) → a NATO or a OTAN (Organização do Tratado do Atlântico Norte)
• IMF is a fund (fundo, m.) → o IMF or o FMI (Fundo Monetário Internacional)
• TGV is a train (comboio, m. / trem, m.) → o TGV (Train à grande vitesse)

Added.

• Sometimes the noun is implicit as in "the MI5 (Service)" → o (Serviço) MI5.
• The same rule applies to Portuguese acronyms like o IST, which stands for Instituto Superior Técnico, where instituto is a masculine noun.

Answer 2

Yes, they do. Generaly the same rules used to determine the gender of a word in Portuguese are applied; an example of these rules is checking wheter the word ends in a or in o. For instance, it seems natural to me to say a NASA, a NSA, but not a FBI and rather o FBI.

However, there are no fixed rules on which to use, so you'll just use which ever sounds better.

Answer 3

Acronyms are written just like they were written in words.

Os Estados Unidos da America. Os EUA.

O Reino Unido. O RU.

Foreign acronyms are no different, the only problem is determining the gender of the foreign word.

Most times it takes the gender of the most common Portuguese translation.