HAX - headless authoring experience. Headless is a common technical term to mean the "front end" of an application (part you see now) is not dedicated or dictated to based on the server backend (the part that sent you this website). It frees up integrations an ensures that things produced with our solutions are highly portable, semantic, dedicated in purpose, and small. HAX is commonly used to reference the entire ecosystem we are building.
Web component - A custom HTML tag. Web components is a browser standard that enables the HAX ecosystem to exist at all. Instead of the web being made out of primitive tags like <div> (to space and divide an area of a web-page) we can bundle up an unlimited number of tags in a new tag definition. This means that
HAXeditor - the h-a-x HTML tag and series of web components
HAXsite - A single site like what you are viewing currently. A HAX site uses a site.json file in order to act as it's "database" for organizing static HTML content produced by HAXeditor when hitting save. This defines the structure of content, details about your site, and what theme to render the site with.
HAXcms - is the organizational side of HAXsite. HAXcms provides an over-world (that looks like a video game usually), enabling users to create new sites via a web interface. It's for managing multiple sites and sometimes is referred to as a "multi-site" environment.
HAXiam - is an organizational technology above HAXcms. This enables PaaS and SaaS style implementations of HAX. For example, if you are affiliated with Penn State, you can log into hax.psu.edu and it automatically generates you a copy of HAXcms to build and maintain your own sites. That's a SaaS implementation of the HAX ecosystem.