I mean... it's charge at rest... so electric and static, but in that same sense, there's static electricity in batteries, and static electricity in DRAM (in-between refresh cycles), and any oscillator at the moment when the first time-derivative of charge reaches zero.

I submit that a definition of static electricity as "charge at rest at non-ground potential" is so broad as to exist in any non-trivial circuit and many trivial circuits. Such a definition is therefore less useful than more common notion as electricity generated as a result of physical surface interactions of dissimilar materials.

Calling it "static electricity" is likely to cause reasonably intelligent and well-educated people to conclude it's related to wearing wool socks in Winter while being insufficiently grounded, as opposed to charge being there as a result of normal circuit operation.

Is it really, though -- isn't what happens inside capacitors basically the same thing as we call "static electricity" when it happens between other surfaces? Or, IOW, isn't pretty much anything potentially (Heh!) a capacitor, only pretty much all things except the ones purpose-built as such are really bad capacitors?