What exactly are people referring to when they say "nature" or it is all "natural"?

I do feel a bit stupid for asking but the terms them self seem to be used loosely and easily. I’m not sure I know their true meanings anymore.

Or does it mostly depend on the context? (for me or what I’m somewhat looking for it would be science related or a more definition/straight answer)

Care to drop me some insight or thoughts?

Thank you.