Fungible tokens are an open standard for creating currencies. Fungibility is the property of goods or commodities whose individual units are essentially interchangeable, and each of its parts is indistinguishable from another part. An example is 1 ZIL can be traded for an equal value of 1 ZIL.
Meta Transactions are a broad concept borrowed from Ethereum where it is typically used to load authenticated data onto a smart contract. This pattern is needed for many Ethereum projects including the ‘gasless’ relay system whereby one or more nodes accept transactions signed with a hidden private key and then wrap that transaction in a Ethereum transaction.
In blockchain-based applications, activities might need to be authorised by multiple blockchain addresses. For example, a monetary transaction may require authorisation from multiple blockchain addresses.
A fungible token is unit of currency that can be readily interchanged, it has properties like fiat where 1 unit of currency is equal to 1 unit of the same currency.