How Can I Figure Out My Vision, In Terms Of 20/20, 20/60, Etc., Based On The Prescription On My Contacts Box?

My right eye, which has astigmatism, the box reads:
BC – 8.6
DIA – 14.5
D – -6.0
CYL/Axis – -1.75 010
My left eye, which has no astigmatism, the box reads:
BC – 8.7
DIA – 14.0
D – -7.0

I’m Trying To Figure Out Exactly What Astigmatism Is?

I googled it but I get all this different stuff and I don’t understand how my cornea being shaped a different way does anything. I wore glasses before but haven’t owned a pair in a year. I never had astigmatism before. I went to the eye doctor and she said I have it in both eyes. Can anyone explain what it is. All the information I get is different.