This is similar to Msty's[1] "Delvify" feature that generates links for keywords in a given text, with the ability to "delve" into each highlighted topic.

While I'm unfamiliar with how it's implemented there, I can certainly see this working with multiple rounds of prompting, and possibly some external data sources and human curation to ensure that the terminology index is actually useful to readers.

[1] https://msty.app/