Is there a dictionary for these terms? CUP, EEE?
With Hyatt points you have to track their life to understand when they expire and when they become limited. Your points are tracked in Hyatt UNTIL an actual reservation is made - whether or not it is a Hyatt reservation or an Interval reservation - so there are no "terms" for Interval points.
One of my primary reasons to own Hyatt is for interval access and the favorable exchange rate. 1300 points is a low season Hyatt unit but will pull 3 II studios (3 x 430) in prime season. Or a 1br and a studio (870 + 430). Or a 2br (1300) (all examples for a week) . You get the idea. A prime 2br 2200 point unit would pull more than one week in Interval.
So 12 months before your "home week" you can reserve your home week , or start spending points by making a reservation elsewhere (and you lose your home reservation) . You can make a reservation for any Hyatt availability that shows up online and you have points for. You can also make any Interval reservation for any Interval availability that show up in Interval. You will have a separate Interval account from you Hyatt account .
So once you reach your home week and have remaining points not moved to EE (see below), they go into LCUP - meaning they are only good for Hyatt reservations 2 months into the future - and they expire 6 months later. They are not good for Interval reservations.
But if you move some or all points into Interval extended exchange (EE) 4 months or more before your home week, they are good 2 YEARS from your home week. So if you do that 4 months before they can be spent in Interval during the next 28 months. So EE points stay valid longer than points not moved to EE. But once you move the points into EE they can only be used for Interval - not for Hyatt. And again, they do not get sent to Interval until you make a reservation in Interval - so they are not Interval points but Hyatt points valid to be spent in Interval only.
Any Hyatt reservation cancelled within 2 months of checkin are also restricted to availability 2 months out. But their age determines where they go. If it is after your home week they go into LCUP (with rules previously defined). If it is before your home week, they go into RCUP - same 60 day restriction but available for Interval.
Any Interval reservations cancelled will depend on where the points came from. If they came for EE then they will go back unless they are expired. If they did not come from EE they will follow the same rules as stated before - depending on whether or not they go LCUP or RCUP or not at all because they are expired. Again, EE points are valid longer and help you here.
And this can all get mixed together with points from different years. You will able to track all of your points online and they will show up in CUP (valid and no restrictions), LCUP, EE or RCUP.
The rules are actually simple but the application can get complex - but monitoring them online will help you. And if your primary reason to own Hyatt is for II you can extend the life of your points leveraging EE. I do that with what I know I am going to use in Interval going into EE, then making some Hyatt reservation also and paying attention to the EE deadline. Online also warns you about that deadline - so it is not as hard to keep up with as you think.