what does Validade: Indeterminada on my CIE card mean?

The first:  once you pass age 60, your card is permanent, and doesn't need to be renewed.  Lucky you- congrats!  You do still need to report changes of address to the Federal Police, however.
"RNE" was the "Registro Nacional de Estrangeiros"; the CIE was the ID Card that people like us, who were in the RNE, carried.   The Federal Police called it "CIE", but nearly everyone else called it "RNE", probably by analogy with the "RG", the "Registro Geral" of citizens' ID numbers; Brazilians generally call their ID cards their "RG".
The new Law of Migration did away with the term "Estrangeiro".  The RNE was renamed the "RNM" - Registro Nacional Migratório; the CIE was renamed the CRNM - Carteira de Registro Nacional Migratório.  Valid RNEs became CRNMs when the law changed, however,  and don't need to be replaced for the name change.

Thanks abthree .
Yes, i can confirm for all others that might ask, the FP doesn't want to bother with us oldies anymore 
60+ and you are home free, even if your card was issued before you became 60 but expires after you past 60!

All the different names on the card - however - i am not sure what it means, mine still uses the term estrangeiro .. and it's brandnew!
But, no problem, they can call it whatever they want as long as it does whatever we expect, right??

Would you know what such a RESIDENTE card that does not expire anymore means in terms of travelling abroad??
Is there a time limit for which we can stay abroad, 1 year, 2 years, less or more??
I guess if i return within that time limit i now can also just book a one-way flight into Brasil instead of a return i won't use??

Yes.  You can stay out of the country for up to two years, and your card remains valid.  Longer than that, unless you clear it with the Federal Police, and it's automatically canceled.