Go to their website and spec out a Tesla. When you get to the self-driving part. Find me where they define either term.
Basic Autopilot is included with all Teslas now (standard as of April 2019), so it isn't an option you can select anymore in the configurator like it used to be. Enhanced Autopilot also is no longer offered, so the only upgrade listed is for FSD, because that's the only upgrade available now. It is listed separately from the included features and basic upgrades like paint color, wheel choice, and interior options.
The relevant linked support page at https://www.tesla.com/support/autopilot goes into specific detail about what is included with both currently available options.
All the functions listed with the FSD upgrade, are NOT included with basic Autopilot and never have been. Enhanced Autopilot, when it was offered, included all the currently listed FSD options other than Autosteer on City Streets and Traffic and Stop Sign Control.
I used the Model 3 for reference, in case different options are there for higher end models.
want you to specifically notice that “Auto lane change” and “Auto steer” (Which are simply “autopilot” features) are present on that definition.
Well, you're wrong there. Auto lane change is NOT part of basic Autopilot and never has been. That is part of Enhanced Autopilot and FSD. Also, there are two options for Autosteer listed and differentiated based on road type. Autosteer under the Autopilot option is lane-keeping on highways, it even specifies that in its definition. FSD on the other hand specifically says "Autosteer on city streets".