lack of knowledge or information
Ignorance is 'not knowing'. Most of the time, we don't even know that we don't know. Once we know that we don't know, we can do something about it.
So, knowing one's own ignorance is the starting point. Once you realize that you don't know, you can start your study. And only study resolves the ignorance.
A good news is that there is ample information available on the Internet these days.