(blockchain jargon, terms and definitions)
Zeppelin is a reference to a community of smart contract developers. It is also sometimes known as "Open Zeppelin".
zk-SNARK (zero-knowledge succinct non-interactive argument of knowledge) is a cryptographic proof system that is used to verify a transaction without disclosing the transaction data, and without connecting with the user who initiated that transaction.
Zero-Knowledge Proof is a cryptographic mechanism meant for helping users in representing assertions where output value can be determined easily without any input information.