The reason that this astronomical term is used to describe a particular kind of attack comes from the "nova flame" or "nova blast" of the Fantastic Four's Johnny Storm ("The Human Torch"). This was a power that could do astounding amounts of damage in a single burst, but leave the hero spent and powerless for a time. The term was picked up and used in Champions, and then spread from superhero RPGs to other forms of gaming.
Short version: Str/Con/Dex/Int/Wis/Cha appears to be available for use, but tread carefully.
This is a very gray area, and any advice you get isn't worth much, unless it's from your lawyer.
If you copy all of D&D's design, your work clearly infringes on their copyright, and they can easily succeed in a lawsuit against you. If you copy none of their design, your work doesn't infringe on their copyright at all.
The problem comes when you copy some of their design. If your work is substantially similar to theirs, it's considered infringement. But how similar does it have to be? Courts have come up with many different answers on this, using many different tests.
Short of talking to a lawyer (which is generally a good idea when worrying about legal issues), it might be helpful to look at what other people have done. As you noted in your question, both Pathfinder and Dungeon World have re-used the Str/Con/Dex/Int/Wis/Cha concepts from D&D. This suggests three possibilities:
- This may be such a small thing to copy that it's not infringement.
- It may be infringement, but the copyright owner hasn't bothered to take action.
- The owner of D&D may have licensed the concept for use. (They have licensed some things.)
Sure enough, Str/Con/Dex/Int/Wis/Cha is part of the d20 System, a set of content published by the owner of D&D under a particular license for others to use. Pathfinder explicitly references this license as the source of their authority to use this content.
But if you're going to use the same license, be very careful to read exactly what is and is not covered. Many licenses allow you to use certain content, but only in certain ways. Many require you to license your derivative work according to the same rules as the original work.
Looking at what other people have done only gets you so far. In the end, if you're not sure whether your work is legal, talk to a lawyer.
Best Answer
Just before the AD&D transition from 1e to 2e, several articles appeared in Dragon magazine detailing the "Ecology Of..." various monsters. These reflected the transition of the game itself, moving beyond the simplistic hack-'n'-slash style toward more logical and comprehensive settings, both outdoor and indoor. Published adventuress kept pace, also evolving into more complex and (pardon the term) 'realistic' treatments.
As part of this transition, various monsters initially named for functionality -- such as mind-flayers and carrion crawlers -- were given additional names as being their 'real' or 'racial' titles, sometimes attributed to the races themselves.
Several real-world parallels exist. The Republic of the Union of Myanmar (aka Myanmar) was called Burma for many years until the local name became widely known and used. Various birds are commonly called Wrens, even though their 'true' name (genus) is Troglodytes.
All of these newer and/or alternate names for monsters should be viewed in similar context.