Beowulf: it's the name of our hero and it's the name of his story.
And it's a pretty cool name: scholars like to argue about where exactly it came from, but the most persuasive theory we've heard is that it literally means "bee wolf," as in the two animals. We know what you're thinking: what's a "bee wolf"?
Well, in Old English, there are a lot of poetic-sounding compound words called "kennings." For example, the sea is described as a "whale road" and a throne is called a "treasure seat." So a "bee wolf" —an animal that attacks bees in a wolfish way—is a bear.
It's interesting to think about this animalistic warrior-prince Beowulf and why he and the story of his deeds are called by the same name. It just goes to show that, if today "you are what you eat," then in Anglo-Saxon and ancient Scandinavian culture "you are what you do"—you're the same thing as your reputation.
Of course, what's really up with the title is that there isn't one. Today we call this long epic poem Beowulf, but in the original manuscript, it doesn't have a title, just like it doesn't have an author. Anglo-Saxon scribes didn't care much about those things. So maybe we shouldn't make too big a deal about Beowulf's name being the title.