Fishing poles can be roughly divided into two main categories, according to where they are used: Heavier, longer saltwater or ocean fishing poles; and smaller, shorter and lighter freshwater fishing poles.
Fishing poles can also be identified by their intended use: Fly-fishing poles, bait-casting poles and spin-casting poles. Fly fishing poles, used to dance a fly across the surface of the water, are most commonly used to catch trout.
"Action" denotes how much the rod bends when you press on its tip. The faster the action, the less it bends. "Heavy," "medium heavy," "medium" and so on refer to the rod's strength and lifting power. Heavier rods generally handle heavier lines and thus heavier fish, too.
Graphite, cane and fiberglass are common materials used in contemporary fishing poles. The guides, or rings that keep the line on the rod, are typically made of metal. Some may have a ceramic ring inside to allow the line to glide.
Special types of fishing poles have evolved to catch specific fish, such as catfish and crappies. That's not to say that these poles can't be used to catch other fish (or that these fish can't be caught with other poles), but that they have the optimal characteristics for catching certain fish species.
The fishing rod, reel, fishing line and tackle must all match in purpose and application. For example, you wouldn't put a heavy-duty baitcasting reel on a lightweight, flexible freshwater pole meant for catching crappies.