A number between 8 and 9

Last night, it was a beautiful sunshiney evening.  We felt celebratory, the air was nice and warm, an important report I had been working on all week was complete, and so, we head out for a supper out.

During supper, I was introduced to a new number by my daughter.  She attests that there is a number between 8 and 9 that no else knows about.  It looks like this:
and it is pronounced heref (a.k.a backlesek):
I thought I knew 8, I thought I knew 9, but I realized, in that brief session, that I had never really given any thought to what might be between them.