NS stood for NeXT and Sun. NX was the original prefix before OpenSTEP.
EDIT: I might be wrong about the first part, see my comment below.
EDIT: I might be wrong about the first part, see my comment below.
I do remember people in my circles thinking it stood for NeXT Software (which was likely a more suitable name for its use at the time).
[1] https://developer.apple.com/library/archive/documentation/Co...
> Totally wrong. The NS prefix predated Sun signing on to implement the OpenStep spec by quite a bit. It was either NS for “NeXTStep” or “New System”. None of us can remember which, though, but definitely not NeXT-Sun.