Hey Nathan - AJAX (Async Javascript And XML) was a method of getting data onto a website without having to reload the page. Basically it was the beginning of modern frameworks, back when it was a brand new idea to have JS call your server and then render the new content itself. (JQuery also confused this a bit by making the $.ajax function, which was a fetch helper.)

So yeah, in general AJAX was just an acronym for the idea of "use Javascript to load XML and use that to make rendering decisions". So basically what we do still, only now we use fetch or axios to make the call and often use JSON instead of XML.