can someone explain to me what this is? I'm not new to drumming but I've never heard this term before until someone mentioned it to me about their drum finish. thanks.

basically its a way to apply a finish to the drum shell. Its hardened over the drum so it's more durable than other paints and lacquer. The only downside is that it's low luster so if you were looking for something shiny it's out of the question

here's an article that explains the process of it.
http://my.execpc.com/~davewrit/Powder.html