Saying things like "rain rains"
"thunder thunders"
etc
Rain does not really rain. Something else is doing the raining, and this is the "it" in "it rains". So "it rains" really means something like "the atmosphere rains". But the rain itself does not rain.
Similarly with thunder. Thunder is the actual sound that results from lightning. So thunder nevers thunders – a sound cannot make a sound, it is the sound. It is the lightning that thunders – or makes the sound of thunder.
Verbing is so common. A probably recent very popular one is google.
http://www.gocomics.com/calvinandhobbes/1993/01/25#mutable_48899