YPP does stand for Yards Per Pound.
Generally, light fingering and lace is sold like this. One number represents the ply, the other the thickness or weight as in 8/2, which is size 8 with 2 plys. The larger the number for the thread size, the smaller it is..... so 5/2 and 3/2 are thicker, 8/2, #10, 50/2 is super fine.
Hope this helps.... Oh yeah, it makes sense that the smaller the thread, the more YPP there are.
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