In practice I've never heard anyone use the word "natural" in regards to price movement in a tradeable product, not in the five years I've been working in the financial industry. Sounds like more of a layman's term, perhaps. But the line between short-term and long-term movements is nearly non-existent since one typically affects the other, and the idea that there is any sense of normal price movement that lies behind all that turbulence is fairly naive.