Exit rate is a google metric that shows the rate of exits from a web page. It determines whether the user continued to surf on your website or not. Its calculation is the percentage of total exits divided by total page views.
There are two types of an exit:
1. Unnatural Exits: when visitors unwillingly leave your website due to a technical problem.
2. Natural Exits: when visitors willingly close your website in an explorer.
These two terms often confused with each other. If the user ended the session, by closing the first page in the session, this means he/she bounced. However, if the user clicked another page inside that website then exited, this means he/she exited, not bounced. Bounce rate's calculation is the percentage of total page visits divided by total entrance visits.
Therefore, every bounce is an exit but not every exit is a bounce. Both terms are important and Google takes both of them into account.
If your website has a high exit rate although your main goal is to pull the user deep inside your website, you should consider making some adjustments. In order to decrease it, firstly, you need to understand why people are leaving. Following reasons might be the problem
Additionally, you need to give users a reason to stay more, this is more challenging than just fixing the problems above. You might need to change your conversion funnel.
Here are some useful resources to understanding funnel analysis which you should check out: