Poaching paper?? I don't get it.?

I was reading one of my cookbook\culinary encyclopedias, you get the jist, and i found something that i can't really figure out. A recipe for fish calls for me to put a "poaching paper" over the fish while it's cooking in the skillet. However, the definition that the book gives me of a poaching paper is very vague and i don't understand how to make it. Please someone help me, this could be very useful in the competition I am going into this weekend. Thank you.