The following is the title of a graph.
PV (photovoltaic) Cost Reduction Road Map (2007-2014)
The graph shows "the continued and projected decrease in the cost per watt ($/W) for PV panels." No more explanation.
The X axis shows $/W, and Y axis represents Q407 / Q408 / Q409..., and I don't know what this Q means.
And there is this expression on the graph: Gen 3 Ramp.
Does Gen 3 refer to 3 Generation? And what is Ramp?
-not a teacher-
I found a presentation which is probably the source of your graph (silde #34 in this pdf)
Q407 means 4th quarter of the year 2007. Q408..4th quarter of 2008 and so on.
But I have no Idea what a "Gen 3 Ramp" is.
Please keep in mind that I'm neither a teacher nor a native English speaker.