The weak and flat 10s are basically the same, I think. In both cases, the 6-pin just falls into the gutter instead of taking out the 10. The ringing 10 is when the 6 goes around and behind the 10 pin.
The term "stone" as in "stone 8" or "stone 9" bring to mind hitting a boulder with my fist. Hitting the boulder, it doesn't move or fall over or anything like that. With a stone 8 or 9, it seems like there are a lot of pins flying all over the place, the ball itself has to exit the pin deck somewhere around the 8 or 9, and still it stands. How, among all those pins flying around, is that little 8-pin or 9-pin statue still standing?
SH