An endpoint of a process is its final pointillistic part. The use of 'meets' in the definition requires a mereologic definition of meets, otherwise endpoint and meets are circularly introduced. The only other possibility is having meets as non-axiomatized primitive.
(=> (Endpoint ?A ?B) (And (Temporal-Part-Of ?B ?A) (Not (Exists (?Z) (And (Temporal-Part-Of ?Z ?A) (Meets ?B ?Z))))))