Bear in mind that whenever you see the phrase "resistance level" you're discussing technical analysis, the phrenology of economics.
Fundamentally? You've got a bunch of business majors who are afraid of math who need some technobabble jargon of their own in order to sound official. The best part of technical analysis is that since stuff is always going up or coming down you can zoom in or out until you find the pattern that proves your pet theory.
So when a guy like David Rosenberg says "double top" what he's really saying is "I've fuckin' called the market more successfully than most but if you need some magic signal as evidence that I know my shit, here's something in your language."
It's still just a guy prognosticating on CNBC but he's a guy lots of people listen to.