Zcash is a digital currency, or cryptocurrency, like Bitcoin. (In fact, Zcash was built on the original Bitcoin code base.)
It was conceived by scientists at MIT, Johns Hopkins and other respected academic and scientific institutions.
You can use Zcash to buy goods and services, or you can exchange it for another kind of money, including US dollars, Euros or another fiat currency.
A major difference between most cryptocurrencies and traditional money is that every transaction is tracked and managed on a decentralized, public blockchain, instead of by a centralized institution, like a bank. This means you truly own your money. Most cryptocurrencies expose your full transaction history and holdings to everyone.
Zcash goes above and beyond other cryptocurrencies.
With Zcash, you control what information you share. Shielded addresses and their associated balances are not visible on the blockchain. Payment disclosure and special "viewing keys" can be used to share transaction details with trusted third parties for compliance or audits.