Oh, a typo is when you type something on a typewriter, but you spelled it wrong. Because it's written in ink and you can't erase it they call it a typo!

I mean, I guess you can call it a typo when you make a mistake with a regular pen, but pretty sure they called it a typo because of the typewriter! So yeah, it means they made a writing mistake when jotting down my blood type! They thought one thing, but it was wrong! So it was a type-o!