Not sure if this will solve the problem, but in the aforementioned guide under Section 14, dictionaries are discussed.
I do not see what is happening as being Amazon's fault. Rather I would (and am) blaming the W3C for derailing HTML. For how long have people been screaming for a <footnote> tag? Ten, twenty years? Forget it, because social media and games get preference and they have no use for footnotes, endnotes, summaries, etc.
As an aside, for correctly structured HTML, your glossary should be in the form of a definition list (<dl>). I see that Kindle understands it.