Answer:
It's equally comfortable in an orchestra and a geometry textbook. What is it?
I bind it and it walks. I loose it and it stops.
A dragon's tooth in a mortal's hand, I kill, I maim, I divide the land.
I appear in the morning. But am always there. You can never see me. Though I am everywhere. By night I am gone, though I sometimes never was. Nothing can defeat me. But I am easily gone.
A great mysterious place that the bold have been known to journey into.
What is so fragile that saying its name breaks it?