What makes one a first-generation college student?

I’ve tried looking this up but there doesn’t seem to be any general consensus on what makes a college student first-generation. I’m filling out college applications and when I started to fill in my parents’ education, I realized that I might not qualify for first-generation scholarships as I had thought. Does first-generation refer to actual attendance at college, or does it refer to graduation with a degree?

In my case, both my father and my grandmother have attended college, but neither of them graduated with any degrees.

Thanks in advance for any help!