What is the main difference between " enterprise" blockchain and regular blockchain? We have some blockchain-based cryptocurrencies such as Bitcoin or Ethereum. On the other hand,  we have some blockchain-based frameworks such as hyperledger and R3 that are designed for businesses. 

Question: What is an enterprise blockchain? 

Is it right those permissioned (and/or private) frameworks (e.g. hyperledger and  R3) are considered as enterprise blockchain?
The line between a blockchain and a distributed database (or ledger) is currently blurred (some would say deliberately so given the hype surrounding "blockchains" at the moment). R3 have recently concluded that it does not make sense to use a blockchain for their enterprise use case as financial institutions do not want to publish data on all their transactions to all nodes on the network. Therefore signed messages are exchanged bilaterally on R3's Corda. I am not an expert on Hyperledger but I think it is focusing predominantly on private or permissioned blockchains. These have a chain of blocks (that each contain a number of transactions) but access (ability to transact and verify transactions) is restricted to a finite number of participants. My personal opinion is that if there are transactions being batched into blocks, cryptographically attached to previous blocks and verified by all (or a subset of) nodes on a network then it should be considered a blockchain. Bitcoin and Ethereum are public blockchains. There are no restrictions in terms of those who can transact on it, view it or verify it.