I pulled up some of those spec's examples in Chrome and viewed the accessibility tree, and weirdly it assigns <dt> an implicit role of `term`, even though the spec says that <dt> should be `listitem` and <dfn> should be `term`. I didn't check FF or Safari but I would not be surprised if they did something different.

Given the spotty screen reader support for dt/dd to begin with, I'd steer clear of using multiple `<dt>` s if a11y is top priority, and just modify your content to have one dt per dd. Your single dt text could be "X or Y", repeat the definition twice, etc.

If you're familiar with Jakob's Law, it applies to a11y too, so stick with what users might have seen on other sites.