Firstly, what is bounce rate?
Bounce rate is the percentage of visitors to your website who navigate away after viewing only one page.
So if you have a single page site then your bounce rate will be understandably high.
If you have more than a single page, you obviously hope people look around and visit more than one page. In this case the lower your bounce rate, the longer visitors are hanging around and are engaged by your content.
What is a good bounce rate?