Why is there music on my iphone but not on my itunes?

I deleted all of songs on itunes to clear space. But on my iphone music, there are still like 200 songs that I've never even heard of before and I don't know how to delete them because THEY AREN'T ON MY ITUNES! There's the little cloud thing next to these songs but what does that mean.

Sync your iTunes with your iPhone. That should be how you got your music on there to begin with.