Single parent

So based on a discussion I just saw on another mommy forum I was wondering about your opinions. How do you define a single parent?

Do you think it’s only based on the relationship status?

Do you think parents that are separated but co-parent are still considered single parents?

Or does single parent mean taking care of everything without sharing the responsibility? Covering all the expenses by yourself while the other parent isn’t even in the picture for some reason.

My parents separated when I was around 5 years old, I grew up with my mom and grandma but spent every second weekend with my dad. He always paid child support. I’d still consider my mom a single parent (up until we moved in with my stepfather, but maybe even then) cause she was the one taking care of me. She was the one who taught me discipline and right from wrong, who helped me with school and my personal problems, who was just always there. So I’d say I was parented by her and her alone. My father was always present but no one I’d consider essential in making me what I am today (or maybe he was by not being really involved cause that shapes a kid as well). So for me my mom was a single mom.

EDIT: I’m in no way trying to take away from what single parents are doing without anyone else involved. Anyone who takes care of their child/children by themselves has my highest respect and I hope I’m not offending anyone by this post. If so please let me know and I’ll take it down.