It just means rice that has been cooked and then left to cool. Cold rice fries better...it doesnt get as gooey and clump up. Any leftover steamed or boiled rice that has been in the fridge and chilled is perfect. If you dont have leftover, go ahead and cook your rice as normal, and then spread it on a cookie sheet and then sit it in your freezer for an hour or so, til it gets very cold and dry and is crumbly when you touch it.