What does "Held" in the helpless condition refer to? (Group new to Pathfinder)

[AmonAmarth]

I've spent some time looking into it, but I can't find anything specific...

Is this some sort of magical holding? Based on what I've seen in the rules and on the forums, it obviously can't just be a grapple or a pin, so what is this specific "held" in reference to?

Thanks!

[Joana]

Hold person (or monster or what-have-you)

[Skylancer4]

Spells like Hold Person/Hold Monster or various other effects that cause similar restrictions?

[AmonAmarth]

That's what I figured....thanks!