Pyrex Pie Share definition Flag 1. A pastry baked inside a pyrex dish, then filled with either custard or jam.2. Life's little victories. 1. I baked a pyrex pie today in the oven. 2. Remember to enjoy life's pyrex pies. Pyrex Pie by Mr. Morimoto January 23, 2010 0 0 Get merch Get the Pyrex Pie mug. Buy Now — $32.95 See more merch