A Production Order is a combination of a few different things, and throughout the world, many radio professionals call the different moving parts different things, although they are called different things the fundamental ideas behind the processes are the same. For example, a Sales Person sells a spot, sends the information onto Traffic, Creative and Production before it ends up on air.
A Traffic Order (also known as material instructions) can be added to any production order created in Radio Workflow. This one is probably pretty easy for anyone who has worked in the industry to understand. You sell a spot, then fill out a Traffic Order so the spots can be scheduled. The Traffic Order includes information such as an ISCI Code, Key Number or Ad-ID, the start and end date, the length of the spot, the cart and possibly the cut number. If an advertiser is supplying audio, the project will typically only need a Traffic Order and not a Creative Order as well.
A Creative Order (also known as a Creative Brief, Copy Points & CNA) is the information the creative writers need when writing the scripts.