Hypertext: https://en.wikipedia.org/wiki/Hypertext
JSON is obviously not a native hypertext, any more than plain text or CSV is. You can, of course, embed URLs in it (or any other format) and call it a hypertext. That's usually pointless, as the links will be consumed by code (rather than a human, in the canonical HTML->browser interaction) so if the URLs aren't simply ignored, they will be dealt with generically.
I wrote about this in HATEOAS is for humans:
https://intercoolerjs.org/2016/05/08/hatoeas-is-for-humans.h...