I see “radial” and think radius and go for the equator of the onion, but I think you’re right and say, an onion ring would be an orbital(?) cut.
When I say “pole-to-pole”, I don’t get confused at the terminology, so I go for that and can be confident. The others get me in negation loops around thinking it was one thing and remembering that I got it wrong last time and it wasn’t…which one?