I don’t expect to get one definite answer here, but Google can’t give me one either. Some websites say they’re your second cousin, and others say they’re your first cousin once removed. I’m trying to figure out some family tree stuff so I need to know the difference between the (groups of) terms.
Ah, you’re completely right.
If that person had a kid it’d be your third cousin, but since that person is OP’s parents’ second cousin, they are OP’s second cousin once removed.