Polypores are fungi that are characterized by having a wood-decaying or soil-hiding habit, with the underside of the fruiting body covered by pore-bearing structures (i.e., they are bracket fungi).

The majority of polypores have a hard or corky consistency. Small-pored polypores are fungi with a small-pored underside that is smooth, lacking pores or the like.

Large-pored polypores, on the other hand, refer to those fungi with a wide and flat pore-bearing surface that may eventually break into layers. For example, the true tinder fungi can cause the wood to turn white over time.