The definition of special terms belongs in your Written Description. Then your Claims (which aren’t required for a provisional patent by the way) will be interpreted in view of the definitions in the description, as long as those definitions are clear to a PHOSITA (“person having ordinary skill in the art”).
If you litigate, there will be a claims construction phase. The only way I could imagine your custom definitions will not hold up is if they are contradictory or unclear, such that a PHOSITA would not understand them.
This will suffice internationally.
Disclaimer: I am not a lawyer.